Here are my go-tos. If you're new to Apple Watch, the very first thing you should do on your new one is change the watch face. You won't find third-party options like you might on Wear OS or Garmin, ...
When new Apple ... Watch screen. (If that isn't working, make sure you've updated to at least WatchOS 10.6. The initial 10.0 release removed this handy feature.) There are two ways to add faces ...