I have same problem: after ubuntu 21.10 I setup win10 also and  I see now in ubi boot menu the windows, but system could not to run it only ubi. I used Boot-repair pendrive,it looked like resolved the problem, but not really. win boot problem stayed yet.
Boot is in UEFI/gpt mode both system, no BIOS system, you can see in grub.cfg
here is grub.cfg:
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
if [ "${initrdfail}" = 2 ]; then
   set initrdfail=
elif [ "${initrdfail}" = 1 ]; then
   set next_entry="${prev_entry}"
   set prev_entry=
   save_env prev_entry
   if [ "${next_entry}" ]; then
      set initrdfail=2
   fi
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="0"
fi
if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi
export menuentry_id_option
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi
function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}
function initrdfail {
    if [ -n "${have_grubenv}" ]; then if [ -n "${partuuid}" ]; then
      if [ -z "${initrdfail}" ]; then
        set initrdfail=1
        if [ -n "${boot_once}" ]; then
          set prev_entry="${default}"
          save_env prev_entry
        fi
      fi
      save_env initrdfail
    fi; fi
}
function recordfail {
  set recordfail=1
  if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}
function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}
insmod part_gpt
insmod ext2
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
else
  search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
fi
if loadfont /boot/grub/unicode.pf2 ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=hu_HU
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=5
else
  if [ x$feature_timeout_style = xy ] ; then
    set timeout_style=hidden
    set timeout=5
  # Fallback hidden-timeout code in case the timeout_style feature is
  # unavailable.
  elif sleep --interruptible 2 ; then
    set timeout=5
  fi
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_gpt
insmod ext2
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
else
  search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
fi
insmod jpeg
if background_image /home/api_ubi/Képek/hatter/Velence_aaa.jpg; then
  set color_normal=black/black
  set color_highlight=black/black
else
  set menu_color_normal=white/black
  set menu_color_highlight=black/light-gray
fi
### END /etc/grub.d/05_debian_theme ###
### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
    set gfxpayload="${1}"
    if [ "${1}" = "keep" ]; then
        set vt_handoff=vt.handoff=7
    else
        set vt_handoff=
    fi
}
if [ "${recordfail}" != 1 ]; then
  if [ -e ${prefix}/gfxblacklist.txt ]; then
    if hwmatch ${prefix}/gfxblacklist.txt 3; then
      if [ ${match} = 0 ]; then
        set linux_gfx_mode=keep
      else
        set linux_gfx_mode=text
      fi
    else
      set linux_gfx_mode=text
    fi
  else
    set linux_gfx_mode=keep
  fi
else
  set linux_gfx_mode=text
fi
export linux_gfx_mode
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
    recordfail
    load_video
    gfxmode $linux_gfx_mode
    insmod gzio
    if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
    insmod part_gpt
    insmod ext2
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
    else
      search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
    fi
    linux   /boot/vmlinuz-5.13.0-28-generic root=UUID=6871e4ac-4a38-4b56-92dc-dad92b5651b3 ro  quiet splash $vt_handoff
    initrd  /boot/initrd.img-5.13.0-28-generic
}
submenu 'Speciális beállítások ehhez: Ubuntu' $menuentry_id_option 'gnulinux-advanced-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
    menuentry 'Ubuntu, Linux 5.13.0-28-generic verzióval' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.13.0-28-generic-advanced-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
        recordfail
        load_video
        gfxmode $linux_gfx_mode
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
        else
          search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
        fi
        echo    'Linux 5.13.0-28-generic betöltése…'
        linux   /boot/vmlinuz-5.13.0-28-generic root=UUID=6871e4ac-4a38-4b56-92dc-dad92b5651b3 ro  quiet splash $vt_handoff
        echo    'Kiinduló ramdisk betöltése…'
        initrd  /boot/initrd.img-5.13.0-28-generic
    }
    menuentry 'Ubuntu, with Linux 5.13.0-28-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.13.0-28-generic-recovery-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
        recordfail
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
        else
          search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
        fi
        echo    'Linux 5.13.0-28-generic betöltése…'
        linux   /boot/vmlinuz-5.13.0-28-generic root=UUID=6871e4ac-4a38-4b56-92dc-dad92b5651b3 ro recovery nomodeset dis_ucode_ldr 
        echo    'Kiinduló ramdisk betöltése…'
        initrd  /boot/initrd.img-5.13.0-28-generic
    }
    menuentry 'Ubuntu, Linux 5.13.0-19-generic verzióval' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.13.0-19-generic-advanced-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
        recordfail
        load_video
        gfxmode $linux_gfx_mode
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
        else
          search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
        fi
        echo    'Linux 5.13.0-19-generic betöltése…'
        linux   /boot/vmlinuz-5.13.0-19-generic root=UUID=6871e4ac-4a38-4b56-92dc-dad92b5651b3 ro  quiet splash $vt_handoff
        echo    'Kiinduló ramdisk betöltése…'
        initrd  /boot/initrd.img-5.13.0-19-generic
    }
    menuentry 'Ubuntu, with Linux 5.13.0-19-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.13.0-19-generic-recovery-6871e4ac-4a38-4b56-92dc-dad92b5651b3' {
        recordfail
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  6871e4ac-4a38-4b56-92dc-dad92b5651b3
        else
          search --no-floppy --fs-uuid --set=root 6871e4ac-4a38-4b56-92dc-dad92b5651b3
        fi
        echo    'Linux 5.13.0-19-generic betöltése…'
        linux   /boot/vmlinuz-5.13.0-19-generic root=UUID=6871e4ac-4a38-4b56-92dc-dad92b5651b3 ro recovery nomodeset dis_ucode_ldr 
        echo    'Kiinduló ramdisk betöltése…'
        initrd  /boot/initrd.img-5.13.0-19-generic
    }
}
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/10_linux_zfs ###
### END /etc/grub.d/10_linux_zfs ###
### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###
### BEGIN /etc/grub.d/20_memtest86+ ###
### END /etc/grub.d/20_memtest86+ ###
### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (ezen: /dev/nvme0n1p2)' --class windows --class os $menuentry_id_option 'osprober-efi-3005-212D' {
    insmod part_gpt
    insmod fat
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root  3005-212D
    else
      search --no-floppy --fs-uuid --set=root 3005-212D
    fi
    chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
set timeout_style=menu
if [ "${timeout}" = 0 ]; then
  set timeout=5
fi
### END /etc/grub.d/30_os-prober ###
### BEGIN /etc/grub.d/30_uefi-firmware ###
menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
    fwsetup
}
### END /etc/grub.d/30_uefi-firmware ###
### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
windows bootmaneger here: /dev/nvme0n1p2
error: no such device: 3005-212D
error:file /EFI/Microsoft/Boot/bootmgfw.efi  not such file
Can somebody help me to resolve my dualboot problem?