Steam Deck: bad battery management chip or did thermal paste kill it?

Hey guys, I am trying to repair a Steam Deck.

Previous owner put in an SSD that drew too much power and it burned out the battery management chip. They replaced the chip but the two traces to the battery were ruined. I repaired those traces, the Steam Deck worked fine for the one full day I used it.

BUT it ran pretty hot, so I took it apart, replaced the thermal paste, tried to cover my repair work with solder mask and cure that, and now it doesn’t show any signs of life. I found some of the battery management chip’s connections shorted together by tiny bits of metal, which I think ended up there after my cleaning attempt since it worked before. Could that, or perhaps UV curing have killed that chip? I’m thinking I should try replacing it.

It just shows no signs of life at all. At first I was worried I used too much thermal paste and shorted something near the main chip but the paste says non-conductive.