Mid-2010 MBP not booting

Looking for some direction on this if isn't the right subreddit...

but I've got a mid-2010 MBP that I've been messing with for a few days and now it won't boot anything (recovery USB, internet recovery, AHT, etc.).

I work in IT and have multiple certifications, so get as technical as you'd like if you have any advice to share. The progress bar sticks at around 2/3rds completion. I looked at a verbose boot but the messages were fairly unremarkable (no errors that stood out).