Shame you've been downvoted. Regarding federal agencies, the Constitution indeed means what it says when it says "The executive Power shall be vested in a President of the United States of America." If some agency can wield executive power, it is under the exclusive control of the president. Looking forward to the likely overturning of Humphrey's Executor soon. It's gone in all but name anyway.

Perhaps this will spur some future Congress to take back what they've delegated (like sweeping tariff power)