UPDATE/SOLVED
So I finally found a local place to run diagnostics and 2 different things were broken:
The old liquid cooler had broken and fried the i7 processor. So when I replaced the cooler, the CPU was still defective and returned high temperatures. Then I replaced the CPU, but the new...
UPDATE:
Brand new motherboard installed and temperature instantly went up to 84-90C.
At this point I have no idea what's causing it. I'm going to get a new PSU next I guess.
Ran a stress test and it went up from 54C and quickly climbed up to 100C after less than a minute. The CPU is getting hot because the coolers are warm to touch, but obviously I can't tell exactly how hot just by touch.
You very well could be right about the sensor. I ordered a new motherboard...
So I noticed my CPU overheating to 100C and have been trying for days to figure out what it is. Here's what I know:
Parts:
CPU: Intel i7 9700K (not overclocked, purchased new 2019)
Mobo: MSI Z390-A Pro (purchased new 2019)
Cooler: NZXT Kraken X53 (purchased 2 days ago to possibly solve this...