So, the canceling of Gui#renderEffects breaks my potion effects logic with FluidStatusEffects enabled.
I will be applying a fix for it in beta4 as long as it does not break other things. But you should probably not cancel that right at the beginning of the method as they may break any other mod that will be using this method. Copying the method and rewriting to suit your needs works, but it is not great for compatibility.

You may want to look into simply modifying the variables instead of copying vanilla code.

While it may be a pain to have a bunch of @ModifyVariable mixins, it will be better in the long run as there are a bunch of mods out there that give the users options to move effect icons, some are less configurable than others. I do appreciate that this is disabled by default on your end.