This is the perfect example of a series that didn’t need there to be an explicit confirmation of romantic feelings and still works perfectly. I think people have gotten used to modern yuri of the last 5-ish years that deal with actual romantic relationships, and I’m really glad we have more of that now, but for most of its history yuri hasn’t been a one-to-one equivalent with "lesbianism." I read yuri because I like seeing stories that explore intimacy between girls, a quality of which is oftentimes its ambiguity and uncertain nature.
This series accomplished exactly what it set out to do and it did so beautifully. I don’t feel any sense of disappointment. I don’t begrudge people for wanting something specific from the manga they read, but I feel like you’re setting yourself up for disappointment. I think a lot of readers would benefit from learning to appreciate different kinds of stories.