For core constitutional functions, yes. The only remedy for presidential criminality is impeachment, which can presumably be followed by prosecution.
Under this scheme then, using pardons as an example of an undoubtedly core constitutional function, POTUS could profit to the tune of hundreds of millions of dollars for pardons granted toward the end of a term when there is insufficient time to impeach.
This would have been a much better hypothetical horrible than "Seal Team 6 killing political enemies," that was dismissed as hysterical.
One problem with all this is, outside of Trump, it never comes up or has not in the last 250 years.
Congress could speed it up by enacting some Presidential crimes, though, and get a more sane Court to oveturn/revise the ruling.
After consideration, all presidential immunity should be presumptive, only, the presumption overcome by balancing the "chilling effect" against other considerations.