Look, the federal government has no powers beyond those enumerated in the Constitution.
You seem to think that the founders littered the Constitution with land mines that render the enumerated powers pointless and therefore that the government can just run amok.
The property clause gives the government the power to dispose of land and to manage the land it owns to carry out it's enumerated functions.
There is not a single word in the Constitution that gives the government the authority to manage enormous tracks of land that have nothing to do with carrying out its enumerated functions.