(To play devils advocate, not because I endorse anything Mark Zuckerfuck makes) Threads does support activity pub, and you dont have to follow him on threads.

he should not be in the game.

Carrion by the Divest team works pretty well as a FOSS spam blocking solution in my experience. Another factor is I changed my number a few years back and I dont give it out to anyone unless necessary. I bought a “free” Sim from a company called FreedomPop for when I need to give out a number and I dont want to share my real number. I keep the Sim off Unless I need a verification text.