I too have a very capable smartwatch (fitness watch - Garmin Fenix) and it's remarkable how different my experience with messages and actions are relative to the experience of Garmin users with Apple phones.
Garmin Connect always runs in the background on my Android phone, watching for notifications, pulling data from and pushing data to Garmin servers on my behalf even when I'm not using the app. It's third-party, but it's reasonably well-written and doesn't nuke my phone battery or data plan - Android doesn't need to protect me or their reputation from Garmin. I can always check the weather or look at my daily workouts or whatever on my watch and trust that it's recently been upodated by the phone app phone. Garmin users with Apple phones complain that "Garmin doesn't work" after every iOS update that further hobbles the Garmin background service.
I get text notifications on my watch for any Android apps that provide notifications, and relevant ones (like text messages, whether SMS or RCS) provide an option to reply from the watch. I tap the top right button on the watch and scroll to "OK" or "Thanks" or "Can't talk right now" or whatever one of a half dozen canned responses covers 90% of my needs in this mode, and don't have to dig my phone out of my backpack or otherwise interact. Emails, calendar appointments, clock stuff, music controls, etc. all work over the watch. It's just as privileged as the phone, I'm not concerned about my Garmin intruding on my privacy as protected by Android, I wear the watch 24/7 and it has more data on me than the phone!