I was really hoping they would use the Neverzone as a DBZ style hyperbolic time chamber to train up. But, it doens't look like they will go that route.
I really don't think the Mina's Solarian army would stand a chance if Moon, Star, and Eclipsa went into the neverzone for a minute and trained up a bit.
Star once literally froze time, and actually just a couple episodes froze a whole helicopter in place. There are spells that can turn off gravity. And the spell with no name can consume anything it touches.
If they went in with a strategy, and were willing to all use the spell with no name, defeating Mina using magic would be no problem. They would just need a little bit of time in Hekapoo's dimension to get prepared. But of course, that would be cheesy and dumb, and not really in character for Star to go along with at this point.
Magic is pretty busted in that universe, and honestly, probably should be destroyed (or at least nerfed).