That is incorrect. The federal government can exercise eminent domain against the states, and that is not an old idea. I found it last referenced in a 2021 opinion authored by Roberts[1]
The pertinent text is
>Early cases also reflected the understanding that state property was not immune from the exercise of delegated federal eminent domain power. See Stockton v. Baltimore & N. Y. R. Co., 32 F. 9 (Bradley, Cir. J.). The contrary position—that a federal delegatee could not condemn a State’s land without the State’s consent—would give rise to the “dilemma of requiring the consent of the state” in virtually every infrastructure project authorized by the Federal Government.
It literally calls out that major infrastructure projects would not have been feasible without this power
[1]https://www.law.cornell.edu/supremecourt/text/19-1039
