Based on what I've read, I don't think the MC's low self-esteem has been relevant until the latest chapter (11.2). Besides, it's refreshing to read about a character whose personality (Fishing) is based on something we don't usually see in this kind of story.
Oh man. Nobody cares about this, but I feel really disappointed with this manga. Anyway, I had a bit of hope about their progress as a "couple", but from what I've seen so far, nothing has changed.