Hi @dawud, I would suggest cleaning cooler and replacing thermal paste first. There is a guide on iFixit how to do this: link Of course it will require some skills, especially when taking off x-clamp for first time to not damage mainboard.
Lighting bolt means you can flash your device, e.g by "Windows Device Recovery Tool", although I'm not sure that will work as you water damaged your phone, but you can try if you have nothing to lose. This operation will remove all data from your phone.
