Isn't the entire concept behind Lower Decks is that the Cerritos isn't a big, important ship? The California class only has 13 decks, which is the third smallest ship in the entire series--the only ships smaller than the Cerritos were the Defiant (which was an "escort ship" not intended for long missions) and the NX-01 Enterprise. It's also slower than everything else in the 24th century--while most other ships can handle warp 9 without problems, the Cerritos flies itself apart if it goes above warp 8 for too long. It's not all that strong either, practically every time it gets in a fight it gets its ass kicked.