Somewhere, in the deepest bowels, Skype still lives. I'm sure of it.

It actually does or at least did, until at least a few years ago. When you opened the audio mixer (alsamixer or pulse audio control?) on XFCE, you could still see MS Teams labeled as Skype there. Not sure how it would be now, because I only ever use MS Teams isolated in a separate Ungoogled Chromium browser now, and have given up on the client for GNU/Linux.

Lync is still there, lurking. With Communicator blocking every contact with the outside world. But eventually some message will pass through!