I got the exact same issue but im unsure about the IOS version makes any difference. It could be my defective iphone 14 pro? Phone connected to wifi and it will suddenly dropped off internet connection, I disabled wifi and use cellular data and no internet connection too but my other devices works perfectly fine on the same wifi network. It has to reboot the phone to get back the internet (Wifi/data).
My older iphone 13pro works fine with the same version IOS 16.0.3, it just keep happening on my Iphone 14 pro. I tried reset network settings, factory reset iphone, restore IOS and setup as a new iphone without restoring any backups and it is still the same (Ruled out apps/backup files corrupted). It will happen even the phone was empty.
I tried bringing back to Apple and they've diagnosed everything was fine after a reboot. Well, I dont like to keep reboot my iphone few times a day just to get back the internet connection on my 3weeks old brand new iphone. Anyone got any idea? TIA
PS: Wifi calling, private relay, VPN, Wifi assist everything was OFF.