My wife has a WearOS watch and a really useful setting is to mute phone when wearing the watch and then unmute if you take the watch off or if it disconnects from the phone. Super useful - I've missed a few phone calls before because I've wandered to the back of the house without my phone (which is always muted as I have my watch on) but with this setting I would hear it.
I actually already use Sound Assistant (only one setting which is to open Spotify whenever I press play on bluetooth headphones / car etc.) but it can't do what I'm requesting here.
My phone is always on silent as I have all notifications vibrate on my watch. However, if I take my watch off or walk out of range of my phone I can easily miss a notification or call as my watch won't alert me. What I'd like is a setting to automatically turn the notification and ringtone sound ON on my phone whenever the watch is taken off or disconnects. This feature is already on WearOS and is really good.