I would ask you to go to the bible and support your position. The bible is the only source and it says nothing about any person/human, being a mediator. We are free to come to the Throne of God directly through Jesus Christ alone.
You made the assertion: “The only mediator is Jesus Christ. He alone is the necessary Mediator. “
You evidently can’t support that in scripture, so you demand that I prove your negative? Sorry, that’s fallacious reasoning.
It’s clear that you asserted something which has no scriptural support. I do believe that if you search, you’ll find plenty of meadiator/intercessory prayers and actions, old and new testament.