Have you tried the Nixon methods to etch white tiles to be indelible to scratching off, etc? Curious if our lasers are powerful enough. It involves coating a white tile with some flat white paint, then burning with the laser, and at the end removing the paint with acetone, etc - this leaves a dark etched image burned into the tile’s surface.
Here’s my first ever tile burn with the settings above, with a white tile coated with black paint. My issue is the paint will scratch off easily, although I did apply a clear varnish topcoat but it’s still delicate. I inverted the image to a negative to have the laser burn the black off, revealing the white below. I’m pretty happy with it as a very first go although I wonder if it’ll be brighter with your settings.
I just downloaded Lightburn and I’m playing with it to see if it will do a better job especially if I try to make my own half tone dithered images, although this too is a big jump considering I’ve never done this before!