OP, I too use Abstract Ocean's silicon sleeves. They have the least amount of bulk, provide maximum protection for your FOB from scratches, come in a myriad of colors to suit your preference, while providing maximum access to the 3 buttons without removing the FOB from the sleeve. To me, the only drawback is some colors (like stealth black), pick up and retain lint from my jeans pockets, look scrungy after a few weeks and are difficult to get that lint back off without a wash and scrub (too much trouble) -- IMHO, for that reason, lighter color sleeves are better.
OTOH, I tried Abstract Ocean's premium leather sleeve and would not recommend them... It's bulky with the snap closure, is more difficult to use the buttons while it's inside the (too thick) leather sleeve, and I finally figured out was the source of my intermittent truck and frunk opening as I got in and out of my MS. The old Tesla "fabric sleeves" are no longer available new unless you found a left-over stash of them somewhere, and are fairly bulky and become tattered a lot faster than the AO silicon sleeve. The present Tesla leather covers IMHO are just too bulky to be practical unless perhaps you never put your key in a pocket -- I've never used mine and the next owner of my MS will get two new ones as swag with their new toy.