That’s exactly what I had to do. On the other side I had the exact same issue with the exact same hole (closest to the trim, rear tires). The other rivet went in fine on the rear and all rivets for the front.Maybe try to find a similar length plugs as EV Mud flaps but a bit smaller? Canadiantire should have them.
Bought these from Lowes , they were a bit too thin but once I screwed in the plastic pin it seemed to hold decently and combined with the screws into the plastic panels should be fine.
Took me 20 minutes with these vs wasting 3 hours and breaking skin on my fingers (not to mention the incessant swearing) trying to get the original rivets in.
Maybe Tesla drilled a slightly smaller hole there for some ungodly reason to mess with my head.