I've been wanting to do a survival challenge for a long time where you spawn in a superflat world with a mansion and try to defeat all the Illagers and take the mansion as a home. The problem is I have no idea how to do this and I can find no way to do it online.
Has anyone been successful when trying to do this? If so how do I do it?
You need to add "mansion" to the preset string, like this (I copied the Overworld preset and changed the biome to "dark_forest" (they will only generate in this biome or "dark_forest_hills", which are the same in Superflat) and changed "village" to "mansion". Note that you might want to remove "lava_lake" as they are otherwise quite common in Superflat worlds and will likely burn them down, but this will make it much harder to find lava):