Question - should the watch sync with the phone? Specifically around deleted messages. I delete a message on my watch shouldn't it delete on the phone and vice versa? Or is that not a function that exists?
I have the same issue when I get spam text messages. I delete them from my phone, but they still show on my watch. It's easy to delete them there as well, but it'd be nice if it happened automatically.
The other day I had sent a text message from my watch. Hours later came back to the text conversation wondering why I never got a reply so checked my phone and the text I sent from my watch wasn't there. I replied from my phone and received a reply almost instantaneously. Kind of odd
I've had this issue for years. Rebooting both and repairing did nothing. Finally got a new iPhone 14 Pro last week, and I think the problem has gone away. So there's your answer.
I was having that issue after upgrading my phone without upgrading my watch to the latest software. I'd try making sure your phone and watch are on the same software cycle.