I don't disagree with you, but there is also the implication that Congress cannot compel the DOJ to exercise its responsibilities except through impeachment or elimination of funding.
That’s why Congress has their own police force and who’s in charge of that? Mike Johnson.
You are correct. Originally the power of the purse was thought to be an effective weapon against executive overreach. It actually had worked in the colonies where assemblies limited the powers of the colonial governors by simply not paying them. Now it’s a minor obstacle any Dem POTUS can get around.