Something I do when doing Pixel Art is making things and then, when almost finished, edit the last details with an outline effect.
Doe to performance reasons, I turn on and off outline effects with a shortcut in the last flattened layer.
Now, group layers marked as Blender Type: Anything but Pass Trought have performance issues. They're very slow.

I didn't played too much with blender types so I was wondering if it's a good idea about changing the group layer blender type as pass trought when using Normal blender type and effects off or something like that. Like, for example, avoid processing layers inside that have Normal blender type and 100% opacity.

I understand that there are multiple blender types. Group layers with almost kind of blender types have different a result when adding layers to them. But well this was something I was thinking about.

In short,, avoid processing effects when there are not effects to process. So, this could make things less awkward just turning on and off the effects as I do when editing one group-flattened layer.