@adammunns that is a very detailed question with lots of background. Well done. Anyhow let's see if we can address one issue at a time. Yes, teh 70% isopropyl alcohol was not a good choice since 30% are still other liquids. So you are possibly looking at a possibly immersion that caused a short circuit. Let's address this.
First of the myth of rice as a tool for any kind of immersion accident has long been laid to rest as totally bogus. Rice does not work. It is the equivalent of doing absolutely nothing. Stop continuing to try to charge, sync or otherwise use your phone. This potentially can make a bad situation worse. This may further damage your phone.
The next thing to do is to clean it. Disassemble your phone using these guides [[Topic:Galaxy S20]] . You must remove all EMI shields from the circuit board. If you do not remove those, you might as well not do anything. After you removed those, clean the whole board, connectors and all with +96% isopropyl alcohol. Follow [guide|5825|this guide], and even so it was written for an Apple iPhone 3G all the points are still pertinent to your phone. While you clean your board, check for any obvious damage, like burned or missing components etc. When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Best thing to do would be to clean it with an ultrasonic cleaner, but if you do not have access to one, this will at least help. Once all this is done, reassemble your phone and reevaluate. Until it is cleaned, everything will only be a guess. Even with all this, water damage has only a small chance to be fully repaired, but at least you can give it a try.
As for your replacing your USB-C port, if you just replaced the port, double check your work. At this point I would even suggest to replace the complete daughterboard. [guide|151721]
"fingerprint sensor wasn't working" hopefully not the board but the sensor itself shorted out. Clean and re-evaluate. May need replacement
"moisture inside camera" will not get better. Is going to always have residue on it, even when the liquid has evaporated.. I'd consider replacement.
"and screen having flickering issues before screen became unresponsive" could be the screen but could be the logic board. Re-evaluate after cleaning the board.
After re-evaluation and should you still have issues, you can try this. Use the Samsung troubleshooting guides to narrow it down. Those will tell you which components to check. Use a PDF reader to search in the component layout file, for the components listed in the troubleshooting. i. e. search for L7002 in the pdf file to see where it is located.
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