Looks like you found Hoshimeguri Gakuen (Stellar Cycle Campus). Initially the refuge for OG Game Club members after Brave Group replaced them. They all graduated and went indie though, with only one of them still active (Yuzuriha Honami). The group went on hiatus for a while but recruited some members (from the ones you linked I subbed to Mikado and Mama). I don't know how they work now but previously they pushed the member songs through youtube ads hard which drives subs way up but didn't translate to CCV (2-3view around 100k subs). One of them actually may have graduated because of this (Fugami Nanana, if you remember the Vtuber with a brown paper bag as her head, it's her).
Mikado generally does midnight karaoke, has the most interesting Vtuber "outfit" (basically body paint). Mama (Kuramochi Kyoko) does a lot of Mahjong Soul (with screaming and desk slams), ASMR, and lots of multiplayer collabs (Dread Hunger, Among Us, Feign, etc).
Will look into Sakura since you recommended her.
Indie Rulia Hoshina returns from quite a long hiatus and long time listeners are back in her return stream as well (including English speaking mods).
She does weekend ASMR and Matsuri visited her debut stream.