The end result is still things like “wow, my tumblr account sure is a lot quiet now that all the people I was following because I liked their weird cartoon porn are gone”.
No, FOSTA hit sex workers. Tumblr just decided that lewd stuff would make it hard for Verizon to sell ads, so they banned lewd stuff and anything their shitty algorithm thought was lewd-adjacent. Now they're down something like a quarter of their former userbase, depending on whose estimates you believe; it might be higher. So that'll really help them sell those ads!