I was going to burn a simple .DXF shape in LightBurn. I needed to add a couple of radius that got missed, and they won’t take in the shape.
I thought if I could add them in (the lazy way), I wouldn’t have to go back and redo the dxf file (the proper thing to do).
Which is to say, once the DXF lines are imported you should be able to use the fillet tool to do the rounding without issue - let us know if it doesn’t work as expected.