I think you’d be hard-pressed to find a LinkedIn alternative. It’s too business-oriented for anyone to care that it’s under corporate control. In some sense, that’s the whole point.

My understanding of Friendica is that it’s supposed to fill a niche similar to Facebook. I’ve never used it though.

Every time my GF Nicole joins a new instance, I make an account on there too. She’s a bit of a fediverse chick.