I am not sure open source can reproduce the "LinkedIn experience". I'm also not sure that's a huge loss. That place is a dumpster fire on a steep hill.

Not yet. But it's being brought up often enough that somebody will probably start working on it in earnest. IIRC somebody did start somethit, but I think it was abandoned

Someone from my cooperative is working on something. Very early stage. https://joinprofed.social/status/

Main alternative (not FLOSS, but European) would be XING! as far as I know

That'd be great

problem is you need companies being part of it and barring that you need all the people you have ever worked with being on it.

Code is easy; marketing, making user growth and get your bill paid are hard

We are working on the exact thing. However it is still in its infancy, but there is a desperate need for it. If you'd like to check out our project, visit our very recent community !theBrotherhoodSpace@lemmy.zip or our website