[Linux] Used Timeshift to roll back on LUKS FDE Manjaro install, seems bricked

So yesterday I was having some issues with software performance and thought the correlation was with some system updates I'd done recently. I use Btrfs for my fs, so I figured a quick Timeshift might be worth a try; it's helped in years past.

So I do the Timeshift and reboot, only to be greeted with my normal LUKS full disk encryption login prompt, as is normal. Except this time, after decrypting and seeing "Slot 0 opened", it did not progress to starting my OS.

I rebooted and retried several times, and even left it on for 9 hours overnight, before trying again just now. Nothing. None of the sensible key inputs (esc, enter, F1-12, etc) appear to make a difference, and I am not finding any info online about this, other than "LUKS + Timeshift = don't, but only sometimes".

I need my data more than anything, and I have a second unencrypted disk in the system that is empty after a recent cleanup. I will likely be trying to live usb in, decrypt my main drive, and copy files over to it before reinstalling.

But if there's a way to repair, that might be preferable.