iPhone 13 Pro and home Wi-Fi issues

So I’ve recently had my home Wi-Fi replaced and for some reason if I go out of range and the iPhone reverts back to cellular network then I move back in range it doesn’t rejoin the network I get an error message which says the network is temporarily unavailable please try later, yet if I forget the network and start again it works,

also all the other devices are still connected

it’s strange because my broadband provider said it is the best available by them

I am going to talk to the tech experts at my provider as well

any help would be appreciated

thanks Dave