Thank you for this great thread. I am going to install a safe on the floor of my 2026 between the second row captain's chairs and was looking if I could find a picture of the floor without the carpeting. I was very happy to find your post. Yours is a 2020, correct? Hope it's not too different from mine.
I poked through the carpet with and icepick and found holes in the spots corresponding to your pictures, and now I have to determine if they are threaded; I hope they are. You posted that they were 13mm which I imagine is the hex head size. Do you have a spec on the actual thread, like M10 or M12 coarse or fine etc? If not I can figure it out by buying a couple bolts.
My plan is to put a sheet of black diamond plate steel 24" by 12" over the carpet and bolt it into the holes in the floor. The safe will be mounted to the diamond plate with its bolts hidden underneath. I'll probably use cap head bolts with a torx or hex insert to prevent easy unscrewing. It's not meant to prevent someone from ever getting in if the car is stolen, but to keep the typical thief from being able to access the safe in a quick smash and grab.
Thanks again. I appreciate it.