If you're using food metaphors, then the band moment is the beginning of dinner and right now we're on the appetizers and the full meal is yet to come.
I can't speak for everyone, but for me I read a story like this as in flow, and does the flow feel connected or is it interrupted? Does the flow follow reasonable curves, or is it unusually and even unnaturally jagged? And other such questions. When I look at this story right now, I think all of it fits, I don't think we've reached any satisfying conclusions in the college arc because we haven't reached any conclusion points.
But the basics seem pretty well established:
1) Aya and Mitsuki are together, but not open about their dating with most of their classmates.
2) They are both charming enough that there are clearly other people interested in them on some level though not necessarily pursuing them.
3) Mitsuki has been struggling to find a band she fits into, and this latest one seemed better than the rest.
4) Mitsuki is still popular for her playing even within this band, but the band is social media focused more so than art focused which is not inspiring for Mitsuki.
5) Mitsuki didn't want to be seen comprising her art and herself in front of Aya
6) Aya saw.
There are a number of obvious conflict points with these established, and probably a lot of non obvious conflict points, and right now we're picking at the latest developments but we may pick on ones from earlier later on too. Or we may not, whatever Sumiko-sensei is interested in. Either way, none of these have blown out completely yet in terms of confrontations or conversations between Aya and Mitsuki, they're still just possible points of conflict. Hence, appetizers.