Yes you can tell if an adapter is for DC fast charging (supercharger) because it has the 2 large pins at the bottom that make it CCS (you have to open the rectangular flap on your Rivian).
The J1772 adapter does not have the 2 large pins under the round connector and is used for AC charging...
Not sure what frontrunner uses but I detailed what I used on Overland Ruff Rax on this post scroll down to Sept30. SF Bay Area Rivian Club
I also show how I mounted the Racksbrax quick releases for the awning and shower.
125 after charging in 100 degree Firebaugh last weekend. Well below red line on guage. It does seem to eat up some efficiency when it is cooling the battery back off after the charge.
Do you have the all-terrain upgrade?
I am assuming you are Dual-Motor AWD
Drive Modes
Dual-Motor AWD vehicles come with up to five drive modes:
All-Purpose
Snow
Tow
All-Terrain
Soft Sand (when vehicle is equipped with All-Terrain Upgrade)
Performance Dual-Motor AWD vehicles come with...
Maybe just loose underbody panel bolts?
When mobile service did some work on my vehicle they did not put on fresh loctite and I had a bolt missing and another almost falling out. I was hearing rattle every time I hit a bump...
I detailed in an earlier post which bolts I found loose on my truck and where the are located.
https://www.rivianforums.com/forum/threads/rattling-noise-from-front-and-back.19589/#post-405095