I’m not sure what does this mean. Is it the roundness of the shape (as in the top view), which is easier to make; or the roundness of the depth (as in the cross section view):
In any case, I gave it a try with both roundnesses. A plate with cutout u-shape, circle and a star. It uses extrusion and no any form of CSG. I’m afraid I spent too much time on this demo, more than an hour, so I hope you take whatever you find useful for your project. Good luck.
Here is the demo:
https://codepen.io/boytchev/full/JjzjGzB
