Bezel or Bumper Cover Options
In Aliexpress you can find TPU (Thermoplastic Polyurethane) covers which fit very well the watch case as protection for any kind of sport/use, even barely bothers your eye when wearing it.
Also you will find tempered protective film in case so.
Both my partner and I are having them for our S9 and S7.
Hoping this helps, here is a bit: