IPhone 15 Pro intermittent ‘no internet’ message with SKY Max Hub

For some time now I’ve suffered with the above ‘no internet connection’ when using my iphone 15 pro over the wifi connection to my Sky Max hub.  This can happy several times per day, and only ‘resolves’ when I switch off/on wifi connection on the iphone.  All other devices (ipad, laptop) perform ok.

I’ve followed several suggestions, including ‘hard reset’ of the hub, resetting the iphone network settings, and ensuring ‘WPA3-T’ is selected on the hub wifi (and recent change to WPA2).  These all result in the same ‘temporary fix’ – i.e. a few hours at best.

Problem is, this is now a priority for me, as since having a stroke two months ago, I rely on the wifi connection for ‘phone calls, as the phone signal is pretty dire when I live.

PLEASE, can anyone help?