Basically just the title.
Most social media websites block anonymizers so you are left with the choice: either use nerd media alternatives that nobody uses and nothing interesting ever happens there (like Mastadon, Lemmy, Matrix, IRC etc...) or reveal your identity with the option of being remaining preudoanonymous at best.
Even if they are not asking for your phone number or email (which is rare), you still can't post from a VPN or TOR exit node.

But I would like to be able to have an option of having my ass on both stools:
1) being able to post on mainstream social media;
2) remain completely anonymous so that my activity can't be traced back to me and so I can post the most embarassing shit that I don't want to be associated with me under any circumstances without risking of it ever backfiring on me.

So what I am thinking is proxifying the traffic like this:
traffic first goes through TOR so that the proxy itself doesn't know my real IP address then it goes to a private proxy that website doesn't know about and so it is not blacklisted by the filters.

But are there any tools that would make such a scheme possible?