Is a 1x1x1 Biome Size Instead of the Default 4x4x4 Possible?

Hello, I've been planning this datapack that uses custom blocks where the texture of vanilla blocks changes based on the biome they are in. However I can't find anything on whether it is possible through datapacks to change the default 4x4x4 cube biome placement size to a 1x1x1 cube instead or whether its hardcoded into the game. It would also be amazing if I was able to keep normal vanilla biome generation to that 4x4x4 default, while I use custom biomes with a 1x1x1 placement for the custome blocks. This would make it a lot easier for Java compatibility so that these custom blocks can sit beside each other even despite being from different biomes.