In the words of one of my CS profs, from a few decades ago: "There are only 3 numbers - zero, one, and infinity. And 'one' is often a mistake"
5 different types (default, force_default, normal, override, force_override)
which can be in 4 different places (attribute, node, environment, role) but not all of the types can be in all of the places
PLUS the "automatic" type, which is from somewhere else entirely
Oh and there's inheritance and merging which does not behave intuitively at all because it's not exactly inheritance.
In other words I have early career trauma from someone's extremely unwise priority implementation and am deeply suspicious of ANY priority override system which isn't just code I've written in a normal programming language.