Obviously not all of it, but I would just about bet that it's at least 75% of this thing will be set on Earth. This is almost always a logistic/budget compromise move when a franchise is normally high-fantasy and/or space-based.

Either that, or the filmmakers don't believe in the property, which is even worse. Despite Jo being a hack and an awful person, Harry Potter grabbed people's imagination because it was built around being low-fantasy with Harry serving as an audience insert. The Matrix inverted the trope, but narratively it worked on the same idea. He-Man, IIRC, has some winks and nods to Earth existing, but it's basically high-fantasy, where Eternia and its galaxy are the universe. OG Star Wars, among others, is the model for how you structure something similarly without bailing on your high-fantasy setting. You need you naive hero to refuse the guide's call to action until they have been taught lessons about the broader world, possibly by flambeing their aunt and uncle, but you can do it by starting in a corner of the setting that's more prosaic and "down to earth" without literally being Earth.

This one feels like they wanted Minecraft kitsch, callbacks to the Dolph Lundgren movie, lifting story beats from She-Ra, and limiting how much of the world they had to build/dress/animate, particularly sets and extras. All this for a second- or third-tier memberberries property. I could be wrong, but I think it's going to land with a thud.