Cylinder correction with a UV laser

I have a 5W UV laser and if I try to engrave a glass with cylinder correction it doesn’t do a even marking on the spot that is in focus looks great on the curves area that is not in focus marks inside the glass and won’t give that frosted look, and the same with a rotary with a glass that isn’t straight that has a bulging area
With the 200mm lens is a bit better but still not good

Cylinder correction only accounts for the shape of the engraving, not the focal length.

Your best bet is to focus a little bit into the surface of the material, see this article for more info:

For the tapered items in a rotary, you want to position the object in the rollers such that the engraved bit is parallel to the machine head (a bubble level can assist), and use taper warp to account for the differing radii of the top and bottom of the tumbler/glass:

Yes I do all that but on glass cup if it’s not 100% in focus it will engrave inside the glass not on the surface that’s why I get either the sides or the center frosted,