SCOTUS ruled if something is in the executive branch, POTUS can fire the commissioner. Congress and everyone else explicitly is saying the FTC is in the executive branch, which puts it in a completely different question that regarding the federal reserve.

The ruling in Slaughter was not that president can fire commissioners no matter what branch they are in. It was never established in Trump v Cook that the federal reserve lies in the executive branch.

Your attempt here to falsely portray an inconsistency that doesn't exist. It's a different question as to whether the federal reserve is in the executive branch. You'll have to show the federal reserve is in the executive branch if you want the same ruling to apply or claim this inconsistency.