Xbox Series X power on then off

So last 2 months ive been having issues with the xbox randomly shutting off mid game and like always if im in middle of watching a show on any of the streaming apps, watched tronicsFix video on cleaning the xbox and followed step by step, thought i had sorted the issue so i went to bed woke up next day plugged it in and tried starting it up and now it turns on for few seconds then shuts off
only thing removed was the fan when cleaned then replaced back
after this issue tho i pulls the whole insides outside the shell and cleaned rest of dust off
but to no success

Hopeful its not a cpu issue, I assume it has water damage? More likely (preferable is the heat sensor resistors are damaged)