Evidently, she hasn’t even read the 25th amendment.
With enabling legislation, I assume Congress could delegate authority to itself or to this proposed commission.
25th Amendment
Section 4.
Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.
But, you’d have to get the Senate to go along, and I assume, either the president’s signature or a veto override.