i think this whole manga, and its conclusion was very much faithful to its characters.
Tanaka is a professional woman working in an industry dominated by men. From that standpoint alone i don't think she'd do anything with a coworker. Let alone a coworker she finds out is a minor.
Once she realises what powerful influence she has on Toda's life and work, she suggests that they dissolve their living arrangements, so that Toda can grow on her own, as an artist, and as a person.
Todo is happy about this development, because she has already grown so much that it's not scary for her to live apart, and because she loves and respects Tanaka's input.
The build up to the kiss scene is two pages, the kiss takes up an entire page, and the resultion is another three pages. it's all entirely character driven, and reads as if was written by Toda herself. It feels cathartic. And it feels like love streaming out of both of them. What kind of love? I don't know. And i don't think that's important.
Anyway, as someone with bad brain, I'm very happy this work exists.