Quote from Robert-Frans
I have just one question, hoping for an answer.
How can I make a default world, but with the height variation completely independent from biomes?
At the end of the advanced settings pages are sliders "Biome Depth Weight", "Biome Depth Offset", Biome Scale Weight", and "Biome Scale Offset". These control how the biomes affect the generation. Turn them all to zero for your desired effect.
Just realized that the minimum value for the weight settings is 1. You will have to change the text in the preset code manually instead of in the advanced settings pages.