Baking light problem from always

Hello there. I have never been able to bake the lights in Unity without artifacts. I have a scene made up from low-poly assets from kenney assets. All the settings are default. I have only changed:
1) Lightmap Size to 2k and then to 4k - no result
2) Compress Lightmaps on to off - no result

Models have Generate Lightmap UVs checked to true.
There is 1 directional light on the scene. Here are some of the artifacts:


Questions now:
1) how can I get rid of this? I think the geometry on this scene is really simple
2) is it normal that it takes about 40 minutes to bake this simple scene? (Ryzen 5 3600)

 

I suggest you to try to mess with Generate Lightmap UV settings, try to increase padding (in both lightmap and generate UV settings), check overlapping UVs after baking (choose this view in the panel with shaded, wireframed, etc views). You should also show us your lightmap settings. Also if artefacts appear on stitches between objects, you need to have quite high lightmap settings to make them invisible
And yes, for some reason both Progressive CPU and Enlightened are extremely slow