Unironically she may need to distance herself from that glasses coworker, she's actually a very likeable person but she isn't mentally good for Noa and she doesn't even know she has that effect on Noa. She puts doubt in her and Rihito's platonic relationship and everyone in the office probably knows already that Noa is emotionally sensitive and starved of affection
You are missing the point.
Noa is leveraging her sex appeal knowingly to extract more than a healthy amount of tolerance from Rihito.
She’s become emotionally dependent on Rihito yet still demands (emotional coercion through melodramatic reactions) a monopoly on Rihito’s attention.
Sure Noa is flawed. The solution to this isn’t to cut people off or just get more formal and conciliatory about negotiating her desires. The solution is for Noa to actually commit to being in a relationship that should actually warrant the obligations she demands from Rihito.
Calling their relationship platonic is ONLY defining the relationship by the sexuality. This wouldn't be a problem if Noa clearly wanted Rihito to be attracted, actively tries to be seen that way, and invades boundaries someone only drops for those they are sexually interested in. It’s leading someone on pretty maliciously to claim all this relationship privilege while fervently denying any significance romantically or sexually.