Does the SCOTUS decision today on presidential immunity for official acts address acts that are a violation of the constitutional rights of others? If you have a federal statutory right perhaps POTUS can ignore Congress and break it. But presumably POTUS can’t arbitrarily violate your personal rights under the Constitution.
Or rather, if so, then likewise the next POTUS can arbitrarily punish the previous POTUS, without recourse, and that should act as a strong constraint.