Xbox One X Hyperactive Fan

Whenever I turn my Xbox one X on, the fan starts spinning extremely loudly, and eventually the console just shuts off. Upon restarting, I get the improper ventilation message. I opened the console up, cleaned everything (there was barely any dust) and it still does the same thing. I have replaced the thermal paste 2-3 times now, super cleaned the entire ventilation system and it still sounds like a jet engine and shuts off whenever I start a game (I can assure you I’m putting enough thermal paste). I have even started it up with the fan exposed and it continues to do the same thing.
This problem started after I started a download on a game (Killer Instinct if it’s relevant) and unplugged the console the morning after. It sat dormant in an empty, dry drawer for 3 days. At the time, my wifi was scheduled to turn off around the time I started the download, but I have found no problems with the hard drive. It doesn’t make any noise and it’s completely clean as well. I have scanned over the board and there don’t seem to be any obvious problems I can see with my naked eye but that’s also not to be trusted because I’m an amateur. There were some spots around some corners of the board that it seems liquid may have gotten to, but I haven’t spilled anything in there myself and I’m not really sure (I bought it used from a local shop 6 months prior). The warranty sticker wasn’t gone when opening it but the black heatsink screws did look like someone had been there.
The Xbox has also been updated, completely factory reset, and power cycled multiple times since to no avail. I’ve exhausted every option, even swapped the hard drive with another console’s but nothing has worked yet. I have another one I bought used but the wifi board seems to be damaged or faulty because that one has extreme lag I don’t get on other consoles. I have yet to open that one, nor do I plan to. Both were supposedly checked by the shop, but I don’t think they checked hard enough. If anyone can help it would be greatly appreciated.