In that particular situation, with casting shadows on small beams with multiple overlapping lights, you NEED a higher resolution. I wish UE4’s dynamic process was more improved than this, but it’s not. You can use some dynamic ambient occlusion post process to cover the transitions for shadows in smaller, tighter, lower resolution areas, but that’s only delaying the problem. The only alternative besides that is to literally change your scene so you don’t have small objects casting shadows at all, or make those objects bigger so the transition isn’t as obvious. After 1k, your light bakes will become horrendously slower and drain the memory absurdly. Take a look at your scene in the lightmap density mode to see where you can optimize, and increase what you need to.