Some context for the "scary expression"/"scary eyes" thing.
This is referring to "sanpaku" eyes. it's a belief/perception that some types of eyes are tied to certain personalities or traits, such as being violent/psychotic/a criminal. Kind of like superstitions about blood types for personality/dating compatibility, there's not necessarily a direct equivalent for it outside of Asia/Japan.
A manga with a similar concept is https://mangadex.org/title/32725/hitomi-chan-is-shy-with-strangers
So while it's still a bit of a storytelling shortcut for portraying a character that struggles with first impressions and is misunderstood based on their looks, it's also not pulled out of thin air. That's why initially Itsuki is so happy Tokujira doesn't just freak out when she sees him, like other characters in the story do (the real reason for that becoming apparent by the time you finish the first issue).
For reference:
https://en.wikipedia.org/wiki/Sanpaku
https://www.tsingapore.com/article/sanpaku-eyes-marilyn-monroe-billie-eilish
https://www.tofugu.com/japan/sanpaku/
For example:
"According to Chinese/Japanese medical face reading, when the white part of the eye, known as the sclera, is visible beneath the iris, it represents physical imbalance in the body and is claimed to be present in alcoholics, drug addicts and people who over-consume sugar or grain. Conversely, when the upper sclera is visible it is said to be an indication of mental imbalance in people such as psychotics, murderers, and anyone rageful. In either condition, it is believed that these people attract accidents and violence."