How practical would it be to make a mod to replace all Ominous Banners?

I want to change the design to something more fitting when I use human villagers resourcepack, so ideally I'd like to globally change the patterns on every instance of the Ominous Banner in all structures (including from mods) and on raid captains. What's the simplest method? I just don't want all the manual work of editing every structure one by one.