I tried to control my gamma using the arrow keys but it didn't work and my gamma didn't go up or down.

Do you have another mod that might be using those keys too? Could you try binding different keys to the gamma increase and decrease in the keybinds settings?

No, I don't have any mods that conflict or use those keys at all. Also, I tried with other keys and it worked

If binding them to other keys works, then I still suspect a conflict with another mod. Some mods use different ways to bind keys, which might cause issues. Since I use the default fabric keybind api there is little I can do about this. I guess you'll just have to use different keys for increasing and decreasing the gamma