Why bother? Easier to just call him Shazam.
That's the name of the wizard, and no matter how much Marvel comics (who curiously were still called Timely when the original Captain Marvel run was being published...) passes that name around multiple characters hoping that it'll stick, and how much they try to stick the current holder, Carol Danvers, in everything to try to establish her as relevant (despite no stories that are actually memorable for a good reason), young Batson is till the original, and it would be caving in to sub-legal shenanigans to give in.