There are 5 axioms of Euclidean Geometry. Those 5 simple axioms have a vast number of implications as evidenced by all the theorems in Euclidean Geometry. In the same way there are logical conclusions to the statements in the Constitution. It is settled law that Congress can regulate employment.
Which ones, and how?
You are welcome to research the topic yourself. There are lots of books on the history of labor rights and labor struggles in the U.S. and the role courts have played in this.
But you might be right that the experts on this topic know less than you and that there is no justifiable implied power of Congress to regulate labor markets.
The same vast majority of legal experts, lawmakers, and those knowledgeable on the subject also believe:
That Congress can delegate legislative power to Executive Branch agencies, in spite of the explicit statement at the beginning of Article I that all legislative power shall be vested in Congress, as long as Congress gives an "intelligible principle" to guide the Executive branch agency (Hampton Co. v. United States);
That Congress can regulate a farmer growing wheat for his own use, that never leaves his property, under the Commerce Clause (Wickard v. Filburn);
That seizing private homes, evicting their owners, and turning the property over to a private developer is a "public use" under the meaning of the Fifth Amendment (Kelo v. New London).
Given the above (and those are just a few examples I thought of off the top of my head), I do not accept that what such a "vast majority" believe is a good guide to what the Constitution actually says.
[0] https://www.law.cornell.edu/constitution/articlei#section8:~...