Please post some pictures and the community can help diagnose the problems to better advise.
I’ve had good success with Yeti etching, aka ablating the powder coat. There are similar processes to etch onto naked stainless steel. I have a diode laser similar to yours, mine is Neje E80 Quad Diode (and before that A40640 Dual Diode).
In the former case, see this post for some process setup and info: Yeti tumbler etching - #6 by bLouChip
As @Preece211 implies, less laser power hitting the stainless = better results. The stainless will react to the laser light.
In the latter case, I use a spray on pre-laser coating by EnduraMark; what doesn’t fuse into the stainless gets washed off post laser process.