There's a lot of platforms that do sort of related things, so it's a hard thing to answer. For "finding a job" I've been looking at HN, remoteok, and a bunch of others. For professional networking I use various tools run by former coworkers (mostly Slack and Google Groups). For "blogs" I use HN and Reddit. etc. I don't think LinkedIn does any of those better (my perception, I'm not a current user).

Personally, I'm probably not interested in a LI clone for many of the reasons I stopped using LI. I deleted my LI account maybe 8 years ago, after getting too much spam (and I think some security issue?)