I do have a quandary concerning priest and their gods. Wouldn’t taking the mark of the Absolute pretty much mean you are breaking your oath to your god? And shouldn’t that effect your spell casting?
Being new to 5E, I did read something to the effect that having a belief structure/dedication to a god was the catalyst for spell casting now and not necessarily granted by a god…
If possible I do plan on making an Oath breaker Paladin (if not native, modded in) that aligns with the Absolute (not necessarily worshiping, but using as a source of power kinda like a warlock).