How often do chests respawn? Does the rarity of the chest impact how long it takes before it can respawn? Do puzzle chests respawn? What about hidden environment chests that require some sort of interaction with the world (such as the buried treasures)?
The community wiki and reddit has been full of misinformation and there has been no video evidence that chests ever respawn.
I tested this with an AR 7 rerolled account and collected all chests in the town of Mondstadt during my first day of playing.
Now, 2 weeks later, I went by the same locations and no chests reappeared.
However, it has been confirmed by support that chests DO spawn when your Adventure Rank is raised. They just do not respawn, ever.
This reddit thread has all the video proofs and customer support replies linked, and I urge you to take a read. https://www.reddit.com/r/Genshin_Impact/comments/jeov1j/the_truth_about_genshins_chests