Hello Alex @3Seventh … Nice to see you here !
This what I could recommend you to pay attention are:
- UV unwrap for Lightmaps to avoid bad shadowing on complex elements - I see many artefacts in your scene
- and BaseLightmass.ini setup to avoid strange splotches on walls
I suggest to use:
[DevOptions.GPULightmass]
NumPrimaryGISamples=128
NumSecondaryGISamples=64
Remember that when you upgrade the engine new version (not hotfix release) then you have to change the BaseLigthmass.ini again.
I recommend also to avoid point lights very near some high reflective metallic elements ( like reflectors in lamps GU10 type for example ) cause the you will get some splotches too and probably you should increase the Num params, but it cost a lot of extra bake time.