Let me repeat that. The Tesla Tap does not work on L3 (Tesla Supercharger).Tesla tap is only for L2 chargers, it does not work on the super charger networks and has a 40 amp charge limit.
But I'll add that there are newer versions of the TeslaTap that do handle 50 A (i.e. the 48A max for Tesla L2 EVSE) and that don't have the pigtail (looks more like the Tesla J1772 adapter.
I'll also add that that was a lot of kerfuffle a couple of months ago when Musk announced that he was throwing the Supercharger network open to all BEV. This would, of course, be the salvation of the Rivian driver (or any BEV driver for that matter) but I haven't seen anything further on this recently.