I assume you read the other thread that gets into dithering and Lightburn?
Haven’t tried painting tiles.
I was going to suggest giving it a clear coat, but then saw you already did that.
I have used dry moly lube (and sharpie) to etch glass.
I’ve also tried using the laser by itself on clear glass tiles that had a silvery surface on the back. From behind it turned okay, and looks good when held up to the light (maybe for a lamp or candle
surround?) But then when I focused through the glass to the back side it turned out amazing! (just need to find some square tiles like this)(a little less power would be good too, started to bubble a little)
I wonder what would happen if you painted it with a ceramic paint/glaze like you would fire in a kiln? Not sure if temps get high enough. Would be interesting to try. Maybe next time I’m at Hobby Lobby I’ll check and see if they have anything like that. The other thing that would be interesting to try would be a powder coat. That’s basically a baked on finish.
-S