Garlean attacks aren't magic, so what are they?

[LilimoLimomo]

I always thought (and this might be made-up lore, I don't remember) that just like how Zenos got the Resonance in Stormblood, he could also have been subjected to a number of other body-enhancing procedures, possibly conducted by the same scientist, that gave him all those abilities with the Katanas and also what made him so strong.

There are a few places where the lore implies that Emet-Selch did some manner of aetherical manipulation on his Garlean heirs, and as such my interpretation has been that that's why Zenos is as strong as he is.

In particular, in 4.5 when Hien is defeated by Elidibus/Zenos he says "Magic? With a Garlean body? That's hardly fair" makes me think that Zenos is indeed capable of using magics regardless of the weapons. You could say that's Elidibus doing all the magic, but when we fight him we see that the fight is relatively similar to the Stormblood ones where Elidibus wasn't in his body.

Elidibus can use magic regardless of the body he's in, just the same as Emet-Selch. Remember that before Endwalker, Emet-Selch is always in a Garlean body, and that doesn't stop him from being the world's most powerful mage. I don't remember if Zenos ever actually uses magic, but he's not able to use magic before he "dies"; so if he does use magic after that, my assumption would be that it's something he picks up one he becomes "an Ascian in everything but name".