I consider these examples of "They're not using magic because they're priests; priests just also often learn magic as part of the gig." There's little or no visible distinction between various dark priests and evil sorcerers.
The D&D ones, while mechanically so similar to wizards, do have some dfferences. Some of those do invoke deities.
Assuming you're counting the psychic abilities as magic here (because otherwise I'd have to claim there's no magic in those books), ditto.
Psionics is magic.
Unless you're counting Morgan as a priestess, I'm not even familiar with any of the earlier ones of these that have anything resembling priests who use magic.
Morgan is definitely a priestess in most flavors, and an evil one at that, tho' magic is absent as a positive froce in Nennius, and the Mabinogwion isn't really arthurian, but a source of things Mallory and White stole from. Note also: Once and Future King is so anachronistic as to be hard to read for me.
Merlin is definitely as much a cleric as caster; all the druids in Mallory are. Welsh legend tends to have non-Christian clergy all using channeled power, not personal power. Which is largely the distinction.
My point is there's nothing distinct about priestly mages in most of those that suggests they're different from other mages. Its just a set of skills often learned by some kinds of priests.
Except that they are reliant upon their faith to use the magic, while magicians can be agnostic or even atheist. In some
Christian miracles are absolutely a thing--but you only rarely saw it in fantasy fiction before D&D.
Much hagiography is "pious frauds"... most of it is filled with miracles, most of which have Græco-roman analogues or even renames acts of minor deities within said tradition. Much of the miracle material in the Tanakh/OT is apparently borrowed from Phonecian, Sumerian, Akkadian, and Egyptian sources. And both the Gnostic Christian and Tanakh material is retained into the Quran. The Hagiographies of many of the now removed Brythonic and Norse Catholic saints are literally just the pre-christian myth tweaked. (Which is why Rome decanonized a bunch on the 00's. Ones that had been only locally canonized in the first millennium.) For example, it's noted that by a simple prayer followed by a command, St. Nicholas raised three boys who had been murdered then stuffed into one or more barrels of pickles...
Japanese Mythology has far more use of magic using priesthoods, and much anime and manga attributes supernatural power lent to the priests by the kami (translates as gods or spirits, but the term Kami lacks the inherent power/scope of the European god concept, at least until one gets to Amterasu and Tsukuyomi), while non-priest casters are binding spirits into service by coercion, not supplication nor contract.
Non-christian fantasy miracles from the early 20th C happen in both John Carter of Mars (his ability to tanslate between worlds, and, as a human, to sire a child on Deja, who laid the egg for said child) and Buck Rogers (In the novel and comics, he fell asleep in a cave for 500 years...). Plus some other adventure fiction. And no shortage of children's literature...