Plutonium

JezuzLizard Thanks for Your suggestion!
I did not change anything of the default settings. I play at 4k UHD on my tv set.
The server-list font is way too small for this..

To me the same.
Hard to express, but somehow the XBox One BT Controller feels kind of laggy and quirky.
Totally different to actual games on the same system.
I have no chance to make a kill. This is frustrating.
I was trying to fiddle with the in-game look-around sensitivity and I am now running it with a setting of 9.
But all in all not satisfying.
I saw the recommendation of unticking the last 5 checkmarks in the common settings of the steam condtroller settings. But I realized that they are already set up like this.
The alternative to this would be to end steam when playing.
I will give this a try.