Maybe get a cover like this? Below is just something I googled and is unlikely to fit the Model 3, but just an idea.
Car Window & Lock Control Cover Pet Lock You Out - Etsy
You can probably make a makeshift one for cheap from a wall plate cover (may need to make a paper template and cut one edge with a hacksaw). Then secure with either tape or velcro (or looking at 3d printed version, get a square dowel that fits into the slot of the switch and glue to the bottom of cover).
Leviton 1-Gang Midway Blank Nylon Wall Plate, Black R55-0PJ13-00E
I see in other thread people just make it out of cardboard which is even easier (just need a box cutter and some spare cardboard). Some made a 3d printed one that fits perfectly, you may be able to get a local printer to print out the design for you.
My dogs keep opening the windows!