Just watched Grisaia and fucking love this particular archetype, 10/10. Looking for more characters like any of these:
Kazami Kazuki from Grisaia no Kajitsu
Kanade Tachibana from Angel Beats
Eucliwood Hellscythe from Kore wa Zombie Desu ka
Shiro from No Game No Life
Isla from Plastic Memories
Origami Tobiichi from Date A Live
Cyno from Genshin Impact (male but otherwise great)
Hibiki from Kancolle
Laffey from Azur Lane

Common traits usually include long silver-white hair, staying calm and collected in stressful situations, logical and calculating personality, usually expressionless face and body language, flat voice, emotionally distant and guarded, sometimes cynical humor and anti-jokes.

I'd appreciate any recommendations if you know good anime or manga with this type of character, any genre is fine or even games or vtubers etc. It's great if she's the main heroine but part of a harem or group of protags is good too. Thanks