Changing biome specifications question

Hello. I'm searching for a way to modify 1.21.1 soul sand valley's appearance. I want to remove the generation of soul sand soil completely. 
By now I tried to modify:


    

  1. data/minecraft/worldgen/biome/soul_sand_valley.json
    2. 

  2. data/minecraft/worldgen/noise_settings/nether.json
    3. 

  3. data/minecraft/dimension/the_nether.json
And nothing worked. Soul sand valley still contains soul sand soil.
How can I accomplish my goal?
    4.
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