found already @maxgerhadts comments here
This is just too messy when the devices change the ports again and again (The S2 tends to toggle between port 10 and 4 all the time.),
It tried to compile the display stuff with the S2 mini as board then :-/
Luckily opening a new instance of visual studio works too, but consumes more space on the desktop.
But anyway, the client can’t communicate with the host. Even when they are using the same wifi libs now.
I don’t know what the client script is actually doing, showing nothing in the serial monitor.
Not even the serial prints at the beginning of setup().
No idea how I can encircle the problem now, I could update the arduino IDE now but that comes with the risk that I have two IDEs then which are not going to compile a working code.