could there be a config to disable some sparkle effects, like the armor sparkle? or is there already something like that and I just don't know how to?

Currently there is no way to remove just the effect when wearing armor but you can remove the armor items from the item tag. I'll look into adding a way to disable specific effects.

how do I do that?

You can use a datapack and replace the current item tag with a new one that doesn't include armor.