How do I fix my WLAN problem?

So I have the following problem:

We have a few months a new Fritzbox with a better and faster performance. I connected my mobile phone (Huawei P10 Lite) to the router and it worked well throughout the house.

But now it is so that every few weeks / months I have no connection on the first floor or in the basement. (The router is downstairs) I just have very good connection in the room where the router is. When I restart the router, it works again everywhere. The other devices that are connected to the router do not have these problems.

It is very stupid to have to restart the router each time. Since the WLAN works perfectly for weeks, I do not understand, where then every time the problem lies. There must be another solution, as the router always restart… Something, so it does not even have to come to… I do not understand why it is that I suddenly have a shorter range and after a restart is for a few weeks everything back to normal…

Does anyone know what?

Wi-Fi is dependent on a few things water, wall thickness, other radio networks.

With you, however, that sounds like a fundamental problem. Since it occurs in a rhythm so ask warranty.