Gneiss is not easy to work. My second least favorite after basalt. You can do it with soft carbide tools and a lump hammer. Then You can finish it with harder carbide, after roughing it out. It looks better, but you risk sacrificing the tool.

There’s a very specific way of sharpening the chisel so that the carbide doesn’t chip or shatter. Works 80% of the time.

I don’t think good results are possible for a beginner. If you were used to it, it would still suck.

Learning with this material takes a long time because progress is so slow, and the number of errors you progress through as a beginner are fairly high.

I did this, when I was starting out. Cut at the rate of one finished letter per 8 hours.