It doesn't matter. The supreme court has made Trump immune, Trump has no accountability. He can just do this and face little consequences. Your steelman means nothing. Nor does the opposite.
We're powerless. Trump isn't.
The discussion should be about accountability of his actions first. When he can actually be made accountable then steelmanning and debating his actions in general can come into play because then it will actually mean something.
The SCOTUS ruling I think you are referring to was about crimes commited by the person who happens to be president, and whether they are punishable. (So not stuff like "you need to undo that bad thing", but "you will go to jail for that".) The acts of the executive branch are absolutely still accountable to the Court via suits of legality and constitutionality.
Also, raise hell at your law makers who thought it was a good idea for Congress to give sweeping powers to the executive in the first place.