Thx for the quick answer,
I got it NOT to work on my laptop (Win 10, USB 3.0, from 2016), but with nothing changed (same software downloads) got it running perfectly on the first try on a tablet (Win 10, USB 3.0, from 2019). Hence, the JeVois-hardware is absolutely FINE.
Now i want it to get running on my laptop, because this is where i want to use it for programming. Rebooting did not help. And yes, it disappears when unpluged and it doesn't work in any other environment (AMCap, for example, shows it in devices, but when selected, it shows an error "unable to add source, collapse" ).
I checked the drivers on both systems (laptop & tablet) in the device manager and everything is absolutely identical.
Rigth now, i have no idea why it is not working on my laptop, i hope somebody has ;-)