If I’m not mistaken the Ultra and the Ultra 5G use the same frame assembly so you can swap the boards. Just be aware the 5G model will have some 5G antennas in the frame and you’ll need to take those out if you’re swapping the standard LTE board into it.
You’ll most likely need a screen replacement and you could still have liquid inside the phone. Beware that due to a recent software update, Samsung now disables the fingerprint scanner if the screen has been changed in the A51 and A71 models. https://www.youtube.com/watch?v=zGLQ9ZRn...
Apple didn’t introduce wireless charging until the 8 and X series so it wasn’t a charging coil. That sticker shouldn’t have caused an issue but I know the 5 series has a tendency to have display issues after repairs. I think it has something to do with the display cables or something. Almost every time I’ve repaired them I’ve had to replace the screen.
Phones can sometimes heat up when they first boot up which is pretty normal. But if it remains hot after a while or doesn’t show signs of cooling down you might have a short on your hands. You made sure to disconnect the battery while doing the repair right?
Where did you buy the battery from? There could be a possibility you knocked the lightning port connector loose so open it back up and inspect that. That may need replacement as well.
Re-seat the connectors and while you’re at it, inspect them for any damage or creases. Did you make sure to disconnect the battery for the repair? And where did you source the screen from?
There is no known way to get around the passcode to get the data unless you either backed it up or connected it to a trusted PC with USB debugging enabled.
Your battery should be fine especially if it was a brief dip in the toilet. It thinks there’s water in the port probably because of a short between a couple pins in the port. Try some rubbing alcohol on a toothbrush to scrub inside the port. You can gently push the bristles into the port to scrub the inside. Let it dry for a couple minutes and then try to charge it. If it continues you’ll probably need a charge port replacement. Thankfully the port is on a separate daughter board which means replacing it is pretty easy. The downside is it takes after the 1st gen pixel design in that the screen needs to be lifted off to get to it. You’ll need to be really careful about removing it but you should order a replacement screen to have on hand as it’s quite easy to break.
If you’re after your files find a donor device. The screen can be damaged as long as the touch, picture, and battery work. You can swap the board from your device (the one with the files you’re after) into the frame of the donor. Just take your time and be patient and as long as you didn’t damage anything else, you’re ready for the next step. You’ll need to power the device on to enable USB debugging mode. You’ll want to have the wireless charging coil screwed into it’s proper place so it can make contact with the board. The reason being is the coil has a temp sensor on it. Without it, the phone will think the temperature is too low and won’t charge.