AreWeGaming - This is in the context of UEFN, so “your” response may create more confusion than solutions. (“your” in quotes because I suspect that it is an AI written response)
As for using the skydive volume to swim underwater, that method may still be broken.
You have an alarming number of volumes under your Island, I’m also noticing duplicate ‘VK Waterbody Ocean C’ in your outliner.
I’d experiment with placing water in a new empty level, also create a new level and observe how the water is setup, and then take your learnings into your map and clean things up.
Let us know if you have any other questions.