The Satanic Temple is actually really bad at "their thing." They lose the majority of their cases and their primary attorney has been repeatedly sanctioned. They're 1A grifters.
If you actually care about 1st Amendment protections you should be supporting groups like FFRF or the ACLU instead
True FFRF is key. ACLU is also pretty damn good.
I honestly like the flashiness that Satanic Temple uses, but when it comes down to doing the work I trust FFRF.
They're fine for doing the occasional attention grabbing malicious compliance style stunt, but they're terrible at the actual nitty-gritty of winning in court.