Kaveh Hangout,
Hidden achievement "School Days",
Start with "The Temple of Wisdom",
You can pick any option there, that doesn't matter but after the conversation, don't forget to click on 3 books so you can get achievement.
Take care my dear player ^^
Additional links:
All achievements (hidden included): s.miroxik74.xyz/g-achievements
Simple interactive map: s.miroxik74.xyz/g-map-sample
Official interactive map: s.miroxik74.xyz/g-map-hoyolab