You need most of the items in the chest to trade skins with Kollector in Goro's Lair. Maybe there are timed chest. But I think Kronikas spheres are time based.

Yup. Behind the two soul chests on The Pit bridge's closet thing, there is a chest hidden there you have to use Kenshi's blindfold to open. For me it cost 850 koins but I cannot remember what it gave me.

https://m.ign.com/wikis/mortal-kombat-11/Krypt_Walkthrough_and_Guide#The_Central_Courtyard

So far this is the most put together walkthrough of the krypt. Youll see where hidden cheats are

KOOL! Reminds me of the Lens of Truth & the Shadow Temple in Ocarina of Time.

Ka-Tra

Well, they got my fear to put on the blindfolds :). Damn that scared the shit out of me. At first I thought: "Wow, it's so nice here, I hope they make it VR compatible". But knowing what is coming at me when I put the blindfolds on, I don't think I would survive.
But is there something in the center of the courtyard, because if I put my blindfolds on at that spot, it seems to spawn them a lot (or is it just coincidence?).
There is also a blank area I can see on the map and I also can see if at the back of that forging contraption. But I can't see yet how to get there.

But because those hidden chests are more difficult to find and what scares could be attached to it, I thought the rewards could have been better.