In pretty much every case, if the moisture indicators on computers, phones etc indicted the device was in moisture, it was in moisture, full stop, do not pas go. If the device warranty excludes moisture damage, then I have no idea why anyone would consider that an "excuse" other than the fact they were not happy with the warranty terms (which doesnt make it an excuse).
I have no idea if there is a moisture indicator in / on / around the area in question in a tesla, and I dont work for apple but our company has used apple devices for quite some time (since the original iPhone).
I have seen phones / macs etc where people swore "no I didnt drop it in water" who straight up lie to your face, because its clear, not only from the moisture indicators but other indicators once the device is taken apart.
Back to this OP,
We have a statement from them that they "drove the car in very heavy rains" and also asked "how deep would the water have to be, to cause this damage?" There isnt any reason at all to ask that question unless someone drove through "some" water but thought "its not that deep / I should be fine".
I have zero idea how much water that would take (to damage those items) but its likely the OP drove through "some" water. Checking the internet for "illinois rainstorms 2021" results in this as the first hit:
Updated Friday at 10:50 p.m. Updated Friday at 10:22 p.m. Updated Friday at 8:56 p.m. Updated Friday at 8:52 p.m. Updated Friday at 8:32 p.m. Updated Friday at 8:21 p.m. Updated Friday at 8:18 p.m. Updated Friday at 8:00 p.m. There are no reports of major damage or injuries after a brief tornado...illinoisnewsroom.org
So, we have severe weather, an OP (who joined today, to make this post) asking "how much water is too much?" when told their damage was caused by water, and water damage / driving through water not a warranty item, yet people want to say "Tesla wants to avoid obvious warranty work!"
After posting this, I spoke to my wife and daughter who were driving it ... I was out of town. They claim that they did not drive in any heavy rain. The car was sitting in the driveway outside when the rainstorms mentioned hit. It is possible that it was sitting in a puddle.
I owned a model S before the Model 3 and I never had any issues with the car and rain regardless of how heavy it was.