It will be VERY challenging. But I think it's easier to make magic consistent in a trio of movies than in superhero comic books which have characters who have existed in them for over half a century. I actually LIKE the MCU going with the "magic being pulled from different dimensions" idea. Even the whole notion of a "multiverse" is actually based on theories in physics. I've always considered Disney's Marvel magic to be very "science-y", if you get my meaning. Indeed, this article from several years ago makes the argument that Marvel Studios has been promoting the idea that magic in the MCU is just "science we don't understand yet.":
https://andphilosophy.com/2017/02/18...atic-universe/
I'm not sure if Feige and company have given up on that idea. I don't mind it personally. Magic being "science" we don't get definitely grounds it in a realistic way. But I imagine a lot of fantasy and magic fans would be pretty upset about that.
I know the DCEU has "sort of" introduced magic into its movies with Shazam! and the Wonder Woman films, but they didn't feel too "magic-y" to me. Zatanna should definitely change that. Emerald Fennell has mentioned how her script for Zatanna will be "scary and intense". That indicates to me that Zatanna will be less of a fantasy movie and more of a horror flick. The horror genre is extremely popular. My brother who absolutely DETESTS superhero fare, LOVES the Walking Dead. So do many other folks. And that's a post-apocalyptic horror television series that's proven to be wildly successful. Heck, practically any show and/or movie these days involving zombies seem to be hits (regardless of quality). So I agree with her approach to the Zatanna flick. The problem is that the Multiverse of Madness is gonna beat Zatanna to the punch!
I actually like how both DC Comics and Marvel Comics (from what I've heard) have been approaching magic lately. Magic having a price is an absolute MUST in MY opinion for any mystical story. Here's an article which basically shares my view on this matter:
https://mystorydoctor.com/the-price-of-magic/
From what I understand, Zatanna has been paying a HUGE price for her magic use lately in the comic books and from what I've read online, a lot of people are enjoying her appearances in Justice League Dark because of it.