Yeah, I figured it out myself and that was indeed the issue.

Thanks for your answer. I'm using UTF-8 on my desktop running Arch Linux and my server running Proxmox.

$ echo -n 'myrandompassphrase123' > keyfile
$ md5sum keyfile
49b3cdce58e65935b8255438266dd87e keyfile

Whereas editing the keyfile using nano and pasting 'myrandompassphrase123' returns 59be855b925013d35476e82763b7a80e.
This is the scenario that's the least concerning, because I get that echoing into a file and editing a file using nano could yield different results. Unfortunately (or luckily) I can't reproduce the 4th scenario, which concerned me.

What do you need that Arch doesn't provide?

I think systemd-boot is a lot easier to configure.

Why are people still using GRUB?

Which one is it?

Thanks for all your comments. Seems like either way is fine. :)

yay -S firefox

Future Breaks https://www.youtube.com/watch?v=k2U8x0ixCZU

Good, but why are there sooo many duplicate communities?

I reinvited you in case you care.

Just commenting to be added as a mod, thanks!