Baking Light Post Process Settings

I’ve been working myself into baking lights in UE5.
Does the Post Process Effect have any effects to the GI?
If I set it to Brute Force or Final Gather for example, or if I just set it to None?
My project settings of Dynamic GI is set to None so Lumen is disabled.

Post process settings will override the project settings, meaning you have set your scene to use brute forced deprecated raytraced GI, not baked lightmaps. In order to use lightmaps, you have to set GI to none and build lighting.

Which one is better? Has better quality?

“Better” is subjective, my opinion is that deprecated raytraced GI is mostly useless. It was deprecated for a reason.

Purely based on image quality, in theory they should produce fairly similar results in static scenes (as long as you crank up the brute force settings)