An example of a similarly tiered hero PL wise might help with the not knowing of mechanical scale. PL10 allows for a decent Iron Man from the first movie, or a Fraction!Hawkeye depending on how you want to play it.
Hammerspace is explained easily as a fluff thing, having your Powers associated with it appear as Devices but without the actual Device cost reduction, so if your Hammerspace Device gets knocked away it just reappears within Hammerspace once it's out of contact. If you want Hammerspace as an actual storage thing, that would be a bit different. Maybe have it follow rules similar to Base building, only with a one or two rank Hammerspace additional cost with the first rank requiring more time to obtain items and the second allowing free action acquisition.
If you wouldn't mind going more into the character as you want them, TBF, I'd appreciate that.
Is Magic a Common tag or a Very Common tag?