I made a 16k stud heightmap, 4k resolution, that I then imported into a blank place. After cleaning it up a bit and reducing my file size from 215mb of just terrain to just over 50mb of terrain, I went to check the terrain outside of studio. It appears the game itself simply cannot load on a server. After waiting for several minutes, nothing. I waited several hours, after going to a friends’ house, and it was still waiting for a server. I can join other games without issue and I have great internet.
Place file, color maps, and raw heightmap files can be downloaded here:
https://devforum.roblox.com/t/terrain-place/598147/