Tips for at least 6 stars?

Pompey is a lost cause at just star for me unless someone can help there.

Any changes to the other teams and what boost I should pick? For reference, main attackers are at level 60 while the rest are level 55; Miyabi, S11, and the 4-star agents have their engines but everyone has level 60 engines, majority have their strongest skills at level 11, level E core skills, and hopefully their best drive discs.