Try to find a slightly smaller impact socket that you don't mind sacrificing to the cause, and hammer it onto the rounded off lug nut. (Use a Big F..kin Hammer!) The socket needs to be super tight and biting into the nut.
If you can do that, you should be able to use an impact gun or a large breaker bar to get the nut off. If it still wont budge, try heating the stud/nut with a torch through the socket driver hole, and try the impact or breaker bar again.
I'll also add this link to an extraction socket made for this job:
https://smile.amazon.com/ROCKETSOCKET-removal-Extract-Rounded-off-vehicles/dp/B07YYP1XD4
I've used both a hammered on impact socket and an extraction socket before (though not on a Tesla) , and it's worked.