SOLVED!
"I finally figured out my problem. I had created a World Partition level while I was creating the landscape, which divides everything into large cubes so you don’t see the distant ones. You can’t disable World Partition without creating a new level.
The solution is:
Select your actor/object and in the details panel, uncheck the box labeled “Is Spatially Loaded.”"
This did the trick, thank god! For anyone who’s running into the same issue.