Troubleshooting Won’t Turn On

So I initially suspected water damage, but I’m not sure that’s the case. I was swimming with my watch and it suddenly started SOS like I was holding the crown and wouldn’t stop. I was able to access all the features of the watch as long as it wasn’t in SOS mode. Then I took the watch off and it powered off completely, and I was unable to force restart it or get it to turn back on. I already tried all the force restart options. I don’t know if it’s a charge, but the device does heat up if I leave it on an Apple certified charger for a long enough period of time.

At this point I took it to Apple , and they basically said we can send it back for repairs, but it’s gonna cost me an arm and a leg. So I’m trying to see if I can fix it myself otherwise it’s just a piece of junk.

I removed the screen to try to see if there was any corrosion or evidence of water damage and I couldn’t find anything. But I did notice when I remove the screen that some lines on the screen itself, which makes me think that it did take the charge at least.

Any thoughts on what’s happening or how I can go about fixing it or even figuring out what’s wrong with it in the first place I can’t tell if it’s a board issue, battery issue, or screen issue.