This mod lets you set fog render algorithm: Linear/Exp/Exp2. You can edit start and end multipler for linear, and density multipler for exp/exp2. You can change fog in two category, generic (ex: overworld) and thick (ex: nether, end). The default values are the vanilla ones. You need to adjust it to your liking. You can open the configuration screen from modmenu mod list -> Configure... button.
Just put fog-customizer-*.*.*.jar into your mods folder. This mod also requires modmenu and cloth-config.
MIT