The big problem is that each deity has their own “signature” that identifies them and their representatives.
In particular, we know from historical experience that holy artifacts are not generally cross religion usable, except for some minor ones.
Meaning that for Holy (magic) Armor to work, you have to be of the same religion as whoever made the armor.
So to do the same thing for/to another deity would require an object made by a priest of that other deity.