I have a series 5 watch that I had not used or updated since I got my iPhone 14 pro max. I let it sit for months and finally decided to use it again. I kept getting the not connected to internet error. I scoured through these forums and tried everything. Nothing worked. Finally I used my roommates phone and was able to update the watch. I recommend doing this before trying all the other stuff. I messed with all sorts of things in the settings and nothing worked and now I’m not exactly sure what I even changed. Oh well, Apple should most definitely have a better fix but they don’t. You would expect a little more out of a trillion dollar company.