Stuck at EFI boot screen

Hi all,

I recently changed the thermal paste on my MacBook, it was working perfectly for a week or so, even running 10-15 degrees cooler. Unfortunately yesterday my screen + touchbar suddenly cut out to black.

After taking a look inside it appears that I was too generous with the new thermal paste and some has snuck onto the other connectors on the gpu. I’ve since cleaned and reapplied new paste sparingly.

My screen is now working again, however it’s stuck asking me for the firmware password, but whenever I enter it the screen will freeze for a few seconds and then the machine will crash.

My understanding is that without being able to enter this password I’m unable to boot into recovery mode/ reset the SMC and NVRAM, if indeed that is the issue.

Ive tried booting into internet recovery mode, it’ll load all the way to 100% and then crash.

Start up disk collector works, I’ll click on ‘MacintoshHD’ and then it’ll crash.
I’m struggling to find much help on Google for this specific issue. I’d like to exhaust my options before having to take it to a local repair shop / Apple; could anyone offer any advice or help? Any ideas as to what’s going on?

Many thanks!

MacBook Pro Mid 2018 15” Radeon 555x macOS 12.1