It's certainly not facially unconstitutional---unconstitutional for everyone in any circumstance---under Wickard and Lopez.

I think your position assumes that the Executive Branch has the power to enact such a law. Some disagree. The "major questions" doctrine will be important.

That's only tangentially a Constitutional question. The executive, of course, doesn't have the power to enact any laws. But Congress has authorized the FTC to make regulations on a wide variety of matters, and this kind of regulation is certainly within Congress's powers under prevailing doctrine.

Is it within the permissible scope of the FTC's regulatory authority under the FTC Act? That I don't know. But if it isn't it will be because of what the FTC Act says, not because of what the Constitution says.

The argument that will be made - and has already been made by Gibson Dunn on behalf of Ryan, LLC - is that the Noncompete Rule violates the Constitution in a number of ways (unconstitutional delegation of legislative power in contravention of Article I; FTC Act's removal protection for Commissioners violates the Vesting Clause of Article II).

For what it's worth, I think that analysis by courts will likely involve the FTC Act, the APA, application of the "major questions" doctrine, and the Constitution. Glad people far smarter than me will be deciding this.

Isn't the same thing as finding it unconstitutional.

be struck down for lack of executive authority.

I think the odds of a nationwide injunction pending review are high.