I don't imagine this'll reach very far (nor can I even see if it does thanks to the new update), but I came across an invite link for Pillowfort, which I have never hear of before but made an account anyways and can now share an invite link myself, so here goes:
I have no clue if it's any good but I figured it's worth having a backup platform just in case (seems a bit more reddit-y than I'd like so far but I'll try it for a bit). The link has a limited number of times it can be used and I can only create up to 3 (plus 10 single-use invites) so in the off chance it runs out let me know so I can make a new one. Apparently you can also sign up without a link through a waiting list and it supposedly doesn't take very long, but who knows if that will remain the case with so many people from tumblr migrating/making backup accounts there.