Cannot boot on Arch Linux after modifying kernel parameters with GRUB

Looking for a way to set my backlights on my laptop running Arch Linux (and Windows on a dual boot), I edited the /etc/default/grub file to change a kernel parameter. Here is what I changed:

# before edition
# GRUB_CMDLINE_LINUX_DEFAULT="lsm=lockdown,yama,apparmor,bpf loglevel=3 quiet acpi_backlight=vendor"

# after edition
GRUB_CMDLINE_LINUX_DEFAULT="lsm=lockdown,yama,apparmor,bpf loglevel=3 quiet acpi_backlight=linux"

Then I regenerated the grub.cfg file with grub-mkconfig -o /boot/grub/grub.cfg and restarted my computer. I have never been able to boot on Arch since. I am still able to boot on Windows though. From an Arch USB live session, I can still access my partitions. So, I first mounted them:

# my root is on the nvme0n1p5 partition and my home on nvme0n1p6 
mount /dev/nvme0n1p5 /mnt
mount /dev/nvme0n1p6 /mnt/home

Then I either did:

mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
mount --bind /proc /mnt/proc
chroot /mnt

or directly

arch-chroot /mnt

and then I edited back my /etc/default/grub file to what it originally was (acpi_backlight=vendor). I even tried to remove completely the acpi_backlight parameter. Then, I did grub-mkconfig -o /boot/grub/grub.cfg and got the following output:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux-lts
Found initrd image: /boot/amd-ucode.img /boot/initramfs-linux-lts.img
Found fallback initrd image(s) in /boot: amd-ucode.img initramfs-linux-lts.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
ERROR: mkdir /var/lock/dmraid
Adding boot menu for UEFI Firmware Settings ...
done

N.B: the ERROR: mkdir /var/lock/dmraid error only shows up when using arch-chroot, not when using chroot. Otherwise, the two outputs are similar.

I also tried to grub-install --target=i386-pc /dev/nvme0n1 but without anymore success. Here is the output of this command:

Installing for i386=pc platform.
grub-install: warning: this GPT partition label contains no BIOS Boot Partition: embedding won't be possible.
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged.
grub-install: error: will not proceed with blocklists.

On my BIOS, I have the following booting path availables :

• SYSTEM 256MB\EFI\arch -> GRUB menu appears and display error: unknown filesystem. Entering rescue mode..., and then a grub rescue> prompt is given;
• SYSTEM 256MB\EFI\Boot -> boots on Windows.
• SYSTEM 256MB\EFI\GRUB -> GRUB menu briefly appears and then brings me back to the BIOS;
• SYSTEM 256MB\EFI\Microsoft -> also boots on Windows;

How can I make GRUB boot back on my Arch session please ?