I would dispute that.

The role of majority leader is not constitutionally defined. His precedence in the Senate is nothing but tradition, and a recent one at that (1937).

He answers to the President of the Senate who could, should she choose so come January, take away his priority recognition and strip him of his death grip.

I explained this further here:

https://ncarteron.medium.com/mitch-mcconnell-an-emperor-without-clothes-c0096ac51e36