And they all have the same problem LinkedIn has -- they don't fix the core incentive issues.
Because you know if any LinkedIn alternative ever becomes popular at some point they'll perform a rug pull to turn popularity into massive profit.
But they won't become popular because they first have to solve the trust issue.
And the trust issue is foundational. And has a solution -- it should be a non-profit and/or consumer co-op and/or producer co-op.
Which likely means it needs to be formed in Europe or Canada or someplace without the anti-co-op laws of the US that make it difficult for co-ops to raise capital.
And founders will have to be satisfied with solid six figure salaries instead of their dreams of becoming a billionaire.
I honestly believe the problem is inseparable from the social network itself. Either you have a space where people can connect and find jobs and nothing more, and you'll have zero engagement and no way to really fund the platform. Or you allow actual social networking (i.e. public posts) and then open yourself up for lots of engagement, and all the associated cancer that comes with that.
Users that thrive in those enviroment stay, others leave. LinkedIn is a scourge to the job market, being force to publish your entire life for everyone to see to find a job is completely dystopic.