I did a thorough Koolit clean, and installed this clip. The clip definitely helps, as the car does not stink, and we're still in pacific northwest rain season... I highly recommend that clip and also started to include that in with my evaporator cleaner tool for Koolit. Adam did a great job diagnosing the root cause and testing the solution...2 cans of Klima and new filters. Follow directions and do 2 full treatments raining each can. I do this every 6 months. Also run with recirculate off unless really needed. The fan runs for 15-20 minutes when parked so leaving recirculate off when parking also helps. Lastly, try one of these:
Cabin Air Filter Clip (Bad Smell Preventer) for Tesla Model 3 and Y
A moisture barrier clip on the bottom of the cabin air filter can keep moisture from saturating the filter and causing a bad vinegar/moldy/cheesy/feet smell in Tesla Model 3 and Y.everyamp.com