Give
Lloyd Mats a shot. Their
Velourtex mats are pretty similar to the Tesla OEM carpet. They do list mats for 2021+ Model S. (they custom make mats on-demand when you order)
Lloyd Mats also have their own anchor/hook system that you can choose to use or not.
I ended up doing this, and it works great. (I don't know if the floor mats in 2021+ MS stay put any better than the older cars, but if they don't - there you go.)
HTH!
Brian