When using the beta v0.5.0 of The Midnight for 1.15.2 MC, the world will get stuck with nothing loading anymore when entering the World Blender dimension or worldtype.
https://www.curseforge.com/minecraft/mc-mods/the-midnight

This seems to be an indication of The Midnight's feature placement somewhere is only terminated when it hits a Midnight block and so it keeps checking downward forever. Which placement or feature is doing this is a mystery. Once found, a PR or issue report to The Midnight will be made if possible or I'll wait until the full release of The Midnight is done and see if it is still an issue.

it appears to be something with the mob spawning in The Midnight. Doing blacklistedSpawns = "midnight*" in World Blender's config lets the world generate correctly. Hmm.

Midnight accepted my issue report that found the root cause of this issue. This will hopefully be fixed in the next Midnight update!
https://github.com/Cryptic-Mushroom/The-Midnight/issues/403