Well, practically there is no real means of appeal if the Supreme Court decides to make law, as they have been wont to do for the last century or so.
Some will say “but the legislature can pass a new law to overrule them”, but then the Supreme Court will just strike that law down as well, if they are intent on making law.
Others may say “but we can pass an amendment”, but you will not be able to pass any amendment on controversial matters that the nation is divided on, and even if you did, the Supreme Court would be the arbiters and interpreters of that amendment.
Yes, we could impeach them to hold them accountable, but Congress much impeach them, and Congress seems just fine with the current arrangement of having the Supreme Court make any laws that Congress wants but cannot pass through the legislature.
Congress can remove or restrict USSC’s juridiction.
Getting them to do that is the trick.