I am not familiar with how Genshin Impact does it. I have a changelog on my Patreon, so if you play from version to version, you should be able to figure out what's new that way.
I see! An NPC with news about accessible quests you haven't discovered yet is an interesting idea, I'll think about how to add that into the game. Maybe a journalist or a beggar whom can tell you what's the "word on the street".
