I knew I shouldn't have picked 'rm -rf /' as a password

Oh, you're lucky. Mine is 'rm -rf --no-preserve-root /'.

Haha, tried that a couple of months back before wanting to do a reinstall. The system stopped me with some warning :) I think it was Arch but could have been Ubuntu or Solus.

There's a way to still do the rm -rf / bypassing the warning but you shouldn't do that.

Ever since systemd was a thing, that command has stopped being 'safe'. It no longers solely affect the filesystem. It can wipe your EFI variables and make your comnputer unable to boot at all, even unable to boot installers to reinstall linux.

https://github.com/systemd/systemd/issues/2402

Don't think of the file system as just the file system. If you keep thinking of / as only meaning 'whatever's in that hard drive' you will not like what you may encounter.

Yep, nowadays rm has a failsafe and requires you to add --no-preserve-root argument if you want to force remove the root folder recursively.

If it's not there, you can always make it be, like I did in past with very similar issue (described in another comment). Quite few people disable/change OS wide keyboards shortcuts ;)