Carbon GT - Aftermarket battery compatible BMS / ESC?

Hey guys, so I bought a used Carbon GT and a boosted v2 for $255 all together, knowing fully well they both had issues that needed to be fixed.

The GT carbon didn’t charge at first, but I plugged in a 36v charger and got the battery out of its dormant state (it had been unused for a few years) and now it seems fully charged.

However, the board won’t turn on, and I suspect the BMS or the ESC is the issue. The battery is an aftermarket battery made by “The battery guy”, and it looks like 18650s, although I’m not sure about the specs, as I haven’t opened up the wrapping. I read on this forum, that aftermarket battery packs don’t play well with the stock BMS / ESC, so could this be the issue?

Also, I noticed a loose screw in the BMS / ESC area, which is definitely not good news, so I’m thinking that might have short circuited something.

What are my options going forward, if I am to get this board working? Would a stock BMS / ESC work with the aftermarket battery pack, or should I look into other solutions? And is there a way to troubleshoot if it’s the BMS or the ESC or something else that is the isssue?

Many thanks in advance!