This problem started a couple of years ago when I purchased an iPhone 12 mini. The phone kept losing connection to the internet whilst still showing Wi-Fi connected. I had to keep toggling Wi-Fi off & on to restore connection. In the house was 2 users of Samsung phones that never experienced any problems at all. I spent a good few hours with Apple experts trying to sort the problem out, but never really getting to the bottom of the problem. It did seem to settle down on its own eventually until recently when it started happening again. I was on TT Fibre 65 until last week when I was upgraded to City Fibre 150 FTTP complete with new Sagemcom Fast 5464-2.T4 router. I was optimistic that it might cure the problem but alas it is still happening. Now whenever the phone is woken from a locked screen it always defaults to 5g mobile data, until I use the phone and it eventually reverts to Wi-Fi. Not sure if anyone can throw any light on this, I am aware of other people having similar problems with iPhones.
