@Stroke_Finger @subluminal @SGS @jonathon @petsam @sammiev
I finally did it! Even though it took ages, it paid off!
The solution?
Solution (Sort of)
I tried the command that the author showed in the end.
efivar -l
It showed a bunch of dump files. So, I did what "the.ridikulus.rat" suggested.
rm /sys/firmware/efi/efivars/dump-* as root and rebooted.
After that, wiped the drive and tried installing and it worked!
Edit: Mentioned the commands here for convenience.