No sound input with Skype

I have some trouble using Skype. I haven’t been able to use my laptops microphone. A test call doesn’t record sound, too. I add two screenshots, one of qpwgraph to show the pipewire setting and one of pavucontrol.
I think there is some malconfiguration with qpwgraph, but I am not clear about how to connect them.

Maybe somebody has a better understanding of this? Thank you in advance!

Problem somehow solved. I switched my German locale to English and it works. Switched back to German and it still works.
qpwgraph shows the right configuration now.

To be honest, I all the time don’t understand the use of “Loopback” devices and I have never realized I configured them as input.