>>2259689ID has good synergy when they're speaking indonesian and can sing. JP has good synergy when they're speaking japanese and can sing.
EN is just a grab bag of drastically different individuals with no synergy whatsoever. Ame needs singing lessons. Mori lives in the future and has other obligations. Ina has an art job. Enma keeps gura locked away in her basement. I don't even like Kiara, but she's arguably the only one whose circumstances actually lend themselves to being a full time Holo idol. And you can't have a group song with just one person. You can barely get en in a group collab for more than 2 hours each month.
There's just no unifying logistics in place even after 6 months, so it looks like EN 1 will have Mukiroze feels when future en gens are far more polished and cohesive. They'll still be the daisenpai, but they'll also seem somewhat detached from one another due to being the only en gen without synergy being part of the hiring criteria.
tldr ID will always have as much synergy as jp because they seem to put a premium on availability and compatibility. Meanwhile future en gens will likely be the synergistic ones just as later jp gens were more synergistic after the disparate daisenpai succeeded at being a proof of concept.