As of 20220926, MakeMKV is broken on Arch Linux due to glib and various other files being updated in Arch but not in MakeMKV. To fix this issue which shows up as a "Fatal error", you must install downgrade from the AUR.

yay -S downgrade

Once that is complete you will need to downgrade a few files.

sudo downgrade glibc=2.35-6 lib32-glibc=2.35-6 gcc-libs=12.1.0-3 gcc=12.1.0-3

The main AUR Arch Linux page for MakeMKV show the same process found here: https://aur.archlinux.org/packages/makemkv