Having WiFi connection problems myself after the android 13 update. I have the galaxy a8 10.4 tablet and have been messing around with loads of different settings with no improvement. Keep getting exclamation mark next to the WiFi fan and the "connected but no Internet". I have found the solution!!! Go into settings, press WiFi then go to "control router", log in to your router, the screen then shows your connection and other specs. Now just hit the home key. Leave the router page and settings page running in the background (don't clear all). I did this a week ago and my tablet is on 16 hours a day and the WiFi hasn't dropped out once....
I think the router page in the background is constantly communicating with the router so it can't disconnect? I think that's why?? Don't care to be honest because it just works