The command is working fine, but for some reason it doesn't recognize the partition as a valid LUKS device. I've also tried another command I found while searching, same result
Oh, sorry, my bad, I was trying to boot the crypto one, but after a reboot it changed position and now it was the sdb, it worked now. I'll try running chroot again
well, not sure why but attempting to restore an old snapshot, even though it didn't look like it worked, allowed me to log in and do a fresh full update. Rebooted after that and worked fine. Only thing I can think of is that I did grub-update when I managed to chroot the installation, so maybe that was enough to make everything work again.