I don't want to downplay her trauma from Kumehei leaving her and not returning after promising but tatsuki is not him ???? Like he proved again and again that he is not like her past bf and he loves her, was even ready to stay just to understand her and be with her.
To me her conclusion doesn't make sense that she wants to breakup so that he can go to Finland and she doesn't worry. You are still going to think about him after breakup, you are definitely still going to formulate some ideas oh he might be with someone else, oh is he happy, oh I will never be in relationship cause these two things happened with me. She is never gonna be happy either ways. The best way would be complete the mass production early, talk to the team and then leave with him and come back. Girl go tool therapy please.