I must be doing something wrong then. I wasn't getting any useful notifications on my watch until I installed all the corresponding watch apps to the phone apps. The watch runs WearOS 3.5. But either way: getting a decent experience should not be this hard.
I've got it the way I like it now but it was a lot of installing software and playing with settings. Which is fun! But it means I would never recommend WearOS to somebody who isn't geeky about Android.
At least with my experience with Wear OS 3.5 and 4, this isn't the case. You can get notifications from any app and don't need two apps to do so.