Did you read the opinion? SCOTUS only said a process was broken by a step being missed. Trump can still fire Cook, just has to let Cook have a hearing about it. Nowhere that I see did they say Trump must at all consider what Cook says at said hearing or be bound by it in any way - only that she must be able to get a hearing. This does not seem to contradict his authority to fire her. Just like your job's HR will gladly give you a hearing about terminating you, even if their minds are all made up and nothing you say will change a thing.
Yes, I read both opinions, and am left wondering why "out of step with the statute Congress enacted and our nation’s tradition of central banking protected from political interference" applied to one and not the other.
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.