Too late, IMO. The invite-only system meant that the "leave Twitter" crowd split between Threads, Bluesky and Mastodon. IMO none of them have ended up being great replacements.
Someone please explain how a social network is supposed to succeed when it's invite-only? Hype alone won't carry it.
IMO, being invite-only is THE reason Google+ failed. There were so many memes about people getting excited for an invite, getting on, and then finding only a couple people they knew were on it, if any at all.
For a social network to work, it needs to be a network. Limiting on-boarding eliminates the network, and so people lose interest fast.