I am also having problems with WIFI. Had iPhone 8 with ios 14.3 it would say its connected to WIFI but was unable to load web pages. Just upgraded to iPhone 12 pro and still having the same problems. I can get it to work and be able to load web pages but as soon as I leave the house or even just lock and unlock my phone doesn't work anymore. I've double checked security settings on my router, checked firmware updates on router, hard reboot on the router, manually assigned IP addresses to my phones, reset network settings, turning off various WIFI settings nothing is helping. I also have multiple other devices in the house that have no problem connecting and using WIFI, Macbook, surface pro, xbox.

Also having issue with Wifi. Tried removing the private address and rejoin network like someone else suggested, didn't work for me. Ive been just having to constantly switch from wifi to network and hope that one will eventually do something.