I have a similar project and, honestly, don't really know what I'm doing but if it helps...
Summary; if you use Decans or Partial Decans to represent the elements of the Deities' portfolio rather than the Deities themselves you can have the tension and overlap you want and a sensible framework for the magic.
The magic in my stories is most similar to Book (as opposed to Path) ritual magic. Divine magic is like Book (Effect Shaping) while Arcane/Occult magic is like Book (Energy Accumulating). Decanic modifiers work, I think, if the Decans represent the 'Domains' or 'Elements' in a deity's Portfolio rather than the deity itself.
In this way the deities in (or between) pantheons can have tension or friction because their portfolio's overlap and the "Power" of a deity vs. another (which is to say; the utility of a god to it's worshipers) can also be a point of contention because of the way Decanic modifiers work to Ritual magic.
It becomes a bit of (fun!) math homework but the number of domains/Paths/elements that can be in a deity's portfolio are easy to fit in as long as your astrology is based on a
https://en.wikipedia.org/wiki/Highly_composite_number like 360... anyhow didn't mean to digress into my own project.