Since the "power sources" of magic are all so wishy-washy and have no cohesive categorization... I pretty much just remove the identities of "divine", "arcane", "primal", and "psionic" altogether.
Instead, as has been mentioned above, magic (or The Weave) just suffuses the Multiverse and all manner of creatures and objects and locations can tap into in and manipulate it in various ways. Each Class just gives us a different way it can occur.
But trying to group different classes together is kinda pointless in my opinion, because the line of reasoning for the different groups doesn't hold up. The Cleric gets their access to tap into The Weave via a grant by their god. The Warlock gets their access to tap into The Weave via a grant by their patron. So were we to group classes together, these two should be in one grouping, but they aren't. One gets called Divine while the other is called Arcane.
Likewise... Sorcerers just naturally are able to tap into The Weave by who they are as creatures and can produce magical effects, which is precisely what Monks and Psions do as well. And yet Monks and Psions get their magic attributed to Psionics, and a lot of people don't even want to call what they do "magic"-- they say Psionics is something else entirely from Magic. Which might have made sense if Sorcerers being "arcane spellcasters" had any kind of important attribution or meaing. But it doesn't... Magic being "Arcane" doesn't really mean anything, so there's not a lot of reason to suggest Sorcerers and Psions are at all different or manipulate different energy.
To me, this is precisely why the whole idea of D&D having "too much magic" never meant anything to me. Because as far as I can see... D&D is a magical world and everything in it has magic-- including the so-called "non-magical classes". The way the game works... the fact that these supposedly "non-magical" classes can reach unheard-of levels of power (up in the high teens all the way to Level 20) and be able to actually harm massively magical creatures like dragons and such with supposedly "non-magical" means... or fall from great heights and not die on impact because of their "hit points" (and then in fact just standing right up and brushing themselves off via a "Second Wind") just tells me that "non-magical" doesn't really exist. To me, "Magic" is merely the D&D substitute word for our real-world "Physics". The same way our real world is defined and explained by Physics (and we couldn't be separated from that if we wanted or tried)... every D&D world is defined and explained by Magic. Which is why all the rules that make up the D&D game are not representative of any presentation of "reality", they are representative of the game worlds of D&D.