Regular WIFI failure

Hello to all,

On a regular base (sometimes several times over a day), without any change to location, router, network, wifi, mi Iphone X (latest IOS version) has troubles reaching internet over the WiFi. The Iphone s the only device having this problem all other WiFi devices (computers and other) can work without any problem. The only work-around is each time to reset the network-config and to reconnect giving the WiFi password.

This means allso that the name of the Iphone (used over Bluetooth connection to the car) changes to 'Iphone X'. If I do not re-change that, bluetooth connection fails on old carkits.

Why is my Iphone having this problem, and how can I solve it?