Honestly what I want most from Tsubomi is a reconciliation with Daidou. Since Tsubomi showed up in the sister dating site manga, I want to see what happens after that fight
Based on https://dynasty-scans.com/chapters/met_my_sister_on_a_dating_site_ch02_2#1 if it's the same continuity, they never met again until the fight, which seems to be years ahead of events from this one.
Now I feel kinda sad, since it seems that even years later Tsubomi is still hung up on Daidou :/
Just speculating here:
I don't think the chapter where they meet again in "Met My Sister on a Dating Site" is set that many years later actually. More like it's after 1 year, 1 year and a half. Also, it's interesting to note that in that chapter, despite the situations in her family, she doesn't speak positively about sister x sister relationships (lol, I know no one speaks positively about that in real life but in the context of the Mochiverse it is strange), so imo it's probable she'll have a fight with her sisters too.
I genuinely feel like Yashiko could be a good girlfriend to her, she seems to care a lot for Tsubomi, but like you said she does seem to still have feelings for Daidou.
All I know for sure is that I want a happy ending for Tsubomi but as of now I don't really see that happening.