I have a large biome world and wanted to check how it would potentially look in 1.18. So I used the re create option but when I go into more world options the world type is custom, not large biomes as it should be. If I try to create a new world and enter the seed manually the large biome option does not exist only default, Superflat, Single Biome, Caves, and Floating Islands are available. 

If I create a world with the re create option where the world type changes to custom I spawn in a completely different biome than I do when the world is set to large biomes.