I miss when Sumire's thoughts were exclusively about Kiyo. Kenta's inclusion has been gradually pushing Kiyo to the background since he's now Sumire's "counterpart" regarding hard career goals so he makes Kiyo's role as homely emotional support look diminishing in contrast.
And what's the most frustrating is that Kiyo stayed in Kyoto specifically because of Sumire, otherwise she'd just go back to her grandma (that is quite old by now). But now we gotta watch this ex-baseball player suddenly being interested in becoming a cook in Kyoto just for love triangle antics.
I don't see it this way.
It isn't like this devalued Kiyo's effort, and Kiyo herself doesn't see her decision as a sacrifice, she accepted she didn't have the drive to be a maiko and found a way to stay on her own initiative, just like she decided to try in the beginning on her own decision.
It is like saying that Suu-chan should only live for one person because of something they wanted to do, it isn't a healthy way of thinking.
Kenta is Sumire's counterpart, Kiyo never really had the same drive for competitiveness, she is strong in her character sure, the way she took responsibility and always thinks about her granny and acts on her decisions are things that inspired both Kenta and Sumire, and both value and love that about her.
I think that if Kenta stayed only in the background this story would have less richness because he brings some things the other two don't have.