This is mostly a rhetorical question. The MCU films are MCU films, and that’s about that.
But they flirt with both sci-fi and fantasy. Magic, of the type Dr. Strange and the Scarlet Witch use, is normally relegated to fantasy. On the other hand, spaceships, laser weapons, and power armour is almost always sci-fi. And then you get the weird middle grounds where you have spaceships pulled by magical goats, or semi-sentient warhammers, or whatever Loki does.
Any technology, sufficiently advanced, is indistinguishable from magic.
Any magic, sufficiently advanced, is indistinguishable from technology.
It’s just a weird thought experiment, I suppose. Most “genres” are social contracts of expectations, after all… nobody says you can’t have elves in your epic space opera, but if you do you’d better have a good justification for it (see “Pandora’s Star” for an example). And likewise, power armour in high fantasy certainly isn’t unheard of, but you have to go that extra mile to justify it.
I’m not much into genre-bending myself. I’m happy to stay in my lane for the most part. Although my pirate epic that I’m planning has some anachronistic elements… stuff that’s “out of time” for the period in which I am writing… but that’s only because I think telling a good story is far more important than rigorously adhering to historical accuracy!
Hope everyone out there is staying safe and healthy!