> Executive orders that violate, or direct the violation of, existing law are illegal

But now we run into the question of What is illegality without ethical-centric courts?

This actually misses the mark. They don't need simply to be legal, they need to have been based upon an existing law or the constitution to be enforceable. In the US the executive can not create law.

That's the theory anyhow. As you mention, the courts now just obey the executive rather than acting as a check and balance as intended.

I think we have that question regardless.