How to fix Apple Watch that flashes white Apple logo on charger?

I previously had an iPhone X and Apple Watch Series 3 42mm (GPS + LTE), but I decided to get a new phone and wanted to trade in my iPhone X, so unpaired my watch before hand. Immediately after unpairing my watch from my iPhone X, the Apple watch never turned back on, so I was never able to pair it to my current phone, an iPhone 11. When I would place the watch on the charger, it would cycle through the white Apple logo and a black screen, but never further than that. I have tried nearly everything I could possibly find on the internet; a force restart, different watch chargers/power adapters/wall outlets, draining the battery for 2 months and then trying to charge it (it would show the red “snake of death” and then begin flashing the logo again). I eventually changed the battery and am still right where I started. When I brought the watch to Apple, they said it would be a $200 repair and that it is possible “water damage”, but I saw no water damage and the inside of my watch was honestly immaculate because I kept it in excellent condition. I believe that this was a software error caused by me unpairing my watch, but I do not know where to go from here, if there is anything I can do beyond this.