There’s already a “check” on the court. The President nominates them and Congress approves them. Also, just because the Supreme Court says something is unconstitutional doesn’t mean it won’t happen.
They have no enforcement mechanism. The President can execute laws how they interpret them. Congress can just pass slightly different versions of the same law. The Supreme Court is the weakest of the branches. People just need to fucking vote in their elections and the problem will solve itself.
If you go visit a small Republican town you will notice that people don’t usually protest, they just donate to politicians and vote. That’s how you win.