There also exists cuda-gdb[1], a first-party GDB for NVIDIA's CUDA. I've found it to be pretty good. Since CUDA uses a threading model, it works well with the GDB thread ergonomics (though you can only single-step at the warp granularity IIRC by the nature of SM execution).

[1] https://docs.nvidia.com/cuda/cuda-gdb/index.html

Is there not an official tool from AMD?

For NVIDIA cards, you can use NSight. There's also RenderDoc that works on a large number of GPUs.

Tangent: is anyone using a 7900 XTX for local inference/diffusion? I finally installed Linux on my gaming pc, and about 95% of the time it is just sitting off collecting dust. I would love to put this card to work in some capacity.