Why is my iPhone behaving abnormally with WiFi turned on?

Suddenly my iPhone stopped many functions dependent on data (Safari, newspaper and other apps, etc.) It makes phone calls OK.

When I turn WiFi off, it appears to function normally.

I first thought my router was bad, but all the other Apple devices here are working fine with WiFi.

I’ve tried turning WiFi off and on repeatedly and shut down the phone and restarted, but the problem remains.

Any advice?