Problem with LVM

So I recently subscribed to a VPS that has 2 x 2TB drives. I installed Ubuntu 20.04 and then I followed this guide (in french) to try to consolidate the space as 4TB (or a bit less ofc) but I am now getting an error.

This is the output of my vgdisplay -v command:

  WARNING: Couldn't find device with uuid A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY.
  WARNING: VG mystorage is missing PV A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY (last written to /dev/sda4).
  --- Volume group ---
  VG Name               mystorage
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                1
  VG Size               <3.59 TiB
  PE Size               4.00 MiB
  Total PE              940679
  Alloc PE / Size       940679 / <3.59 TiB
  Free  PE / Size       0 / 0   
  VG UUID               ImvQ22-0OPa-psI3-Y80o-UknX-86Zj-Ta3S3a
   
  --- Logical volume ---
  LV Path                /dev/mystorage/mylv
  LV Name                mylv
  VG Name                mystorage
  LV UUID                xnMVfF-elmu-WoLg-3Dfy-DQiI-hdD2-ftM13f
  LV Write Access        read/write
  LV Creation host, time ns385746, 2022-03-02 01:47:37 +0000
  LV Status              NOT available
  LV Size                <3.59 TiB
  Current LE             940679
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
   
  --- Physical volumes ---
  PV Name               [unknown]     
  PV UUID               A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY
  PV Status             allocatable
  Total PE / Free PE    463747 / 0
   
  PV Name               /dev/sdb     
  PV UUID               11ENzP-bTbI-rx22-3zCY-KGAo-qT7h-Z9z78t
  PV Status             allocatable
  Total PE / Free PE    476932 / 0

And the output from pvdisplay

  WARNING: Couldn't find device with uuid A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY.
  WARNING: VG mystorage is missing PV A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY (last written to /dev/sda4).
  --- Physical volume ---
  PV Name               [unknown]
  VG Name               mystorage
  PV Size               <1.77 TiB / not usable <4.09 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              463747
  Free PE               0
  Allocated PE          463747
  PV UUID               A6wuiG-M85U-7RT2-GF2w-TYoi-kIOu-53ofCY
   
  --- Physical volume ---
  PV Name               /dev/sdb
  VG Name               mystorage
  PV Size               <1.82 TiB / not usable <1.09 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              476932
  Free PE               0
  Allocated PE          476932
  PV UUID               11ENzP-bTbI-rx22-3zCY-KGAo-qT7h-Z9z78t

Upon doing lvmdiskscan -l

  WARNING: only considering LVM devices
  /dev/sdb   [      <1.82 TiB] LVM physical volume
  1 LVM physical volume whole disk
  0 LVM physical volumes

I'm really new to this. How can I use my 2 x 2TB drive as 1 x 4TB ? Detailed replies are appreciated.

Edit: After running

pvcreate -vvv .... 

I noticed:

  Opened /dev/sda4 RO O_DIRECT
  /dev/sda4: size is 2 sectors
  Closed /dev/sda4
  /dev/sda4: Skipping: Too small to hold a PV
  filter caching bad /dev/sda4

So I ran

sudo cat /proc/partitions

And sda4 is showing as 1 block ?

major minor  #blocks  name

   7        0      63396 loop0
   7        1      63376 loop1
   7        2      68856 loop2
   7        3      69552 loop3
   7        4      44632 loop4
   8        0 1953514584 sda
   8        1    1048576 sda1
   8        2     524288 sda2
   8        3   52428800 sda3
   8        4          1 sda4
   8       16 1953514584 sdb