
I think it's best to be patient and wait out on other character's arc/development, since even though the manga has already published almost 350 chapters, I feel like the story is still somewhere in between early mids chronologically. Besides, we just got some character arc(?) for Lied with the grindy game thing with Nupie, so I'm sure the author is bound to release more about the others soon enough.
I personally think the newest arc about Kerori isn't really about Kerori per se y'know, and more so about her relationship with Gyari, as well as Gyari's own character development herself (not crossing the boundaries Kerori has set for the both of them, and genuinely treating her as a friend and real human (or demon) being rather than as an object.)

Maybe it's just me being biased for the wuhluhwuh happening rn between them, but I for one love this arc. ^^
Still, don't feel pressured for not liking this new story arc :D, since your reasoning is totally valid and I get why you'd feel frustrated as other characters don't really get as much screentime/story arc themselves compared to Kerori
please do not cancel me but I don't quite like this new arc of being kerori as the main center of attraction...again. like has she not have had enough exposure? I think others should have their own arcs as well by this time, kamui has not, gaap not too much, agares not much as well, elizabeth where is her mom is she a romantic as well? you know like there are sooooo many characters and the story only focuses on like 3-4