I would have liked it if the separate 11-minute episodes played off each other, with the first being devoted to Star and the second being devoted to Marco. For example, Marco would be working with the Magical High Commission because there are still anomalies, while Star is getting closer to her mom and Eclipsa, and both of them keep unearthing secrets.
For example, Heinous still chases after Marco before the Monster Bash episode, which makes Hekapoo panic because she doesn't know that Marco was aware of Meteora's existence, so the two of them have a discussion that explains that Star isn't a "real" Butterfly and who exactly Heinous is, and why Star's goal of uniting monsters and Mewmans is going to lead to a disaster. Star, meanwhile, works with Moon and Eclipsa to sneak into forgotten castle areas such as the scribe room to find that evidence is being covered up of the Butterfly's past, and ultimately figure out the MHC has set them up.
You'd get the episode where Marco and Hekapoo work together to close portals, only to realize that Star is the one causing all of the interdimensional breaches, while Star confides in her mom and Eclipsa what exactly is going on in the night, and everyone agrees the best course of action is to bring Glossaryck back... somehow. Both of them encourage her to keep "deep diving", while Hekapoo and Marco realize the best thing they can do is stop Star.
Basically, have Marco and the MHC come to blows with the Star and the Butterfly family, with the season finale being Marco and Star splitting because they have two very different perspectives of the same picture, putting them at odds with each other with what's best for everyone.