I finished Kronos' home quest and Kronos said to go back to the city, but I can't figure out how to proceed. All locations on the map are locked, except areas where I have already completed the quests.
pixel_player21981175 The quest tab would most likely have an "Enter" button that will take you to the city. Or you can visit it from your map as well:
If you're on mobile, it would be the second last button on the bottom bar.
After you talk to Kronos, you can proceed.
Also this page can be really helpful when you're stuck with no new quests, you can see what you need to do: https://wiki.diggysadventure.com/index.php?title=Atlantis_(Quests)
Abhi Thank you. I found it.