Yes, it is hard. Unless you are in the Abyss…in which case it is much easier.
This is one reason demons enjoy proxy fights as much as the deities. Far better to wage war on foreign planes where it’s very hard to permanently loose your entire army.
So as you can imagine, demons don’t like combat in the Abyss…thus for all the various ego maniacs running around and all the drama and conflict of the court…the Abyss itself has been quite peaceful for the last several thousand years. Everyone has pretty much agreed to “take their fights outside” so to speak.
This will actually get a good amount of discussion in book ii, and then I fear it may come home to roost in book iii.