I have already tried many things. I'm at the end of my tether.

I currently have the latest Swisscom router... I have also tried Devolo Powerline 500. (It works to some extent, but not satisfactorily, because it only gives 70MBit/s).

I also tried the Swisscom WLAN box. It didn't work at all.

Now I wanted to try the Swisscom repeater, but someone wrote here that the access point is the better option.

What else can I try? I only have 1 - 2 lines on the upper floor....

Thanks for the help.
Greetings Patric

I have a similar question.

I use a UPC wireless router, but it is too weak.

Now there is a 10m long LAN cable from the UPC wireless router to the location of the future device. Am I looking for a repeater or access point? The position of the future device will be more central in the flat.

WLAN repeaters do not need a connection to the router! They only amplify the WLAN signal!
They just have the disadvantage that the data rate is halved. That's just the way it is with repeaters.
That's why it's better to set up an Acesspoint, and if that doesn't work, think about a Powerline WLAN extender.