I put 2 config files in the github https://github.com/ganzocrypt/xmrig-macos/releases/tag/v6.13.0-dev-macos

I used KawPow on unminable and I played a bit with Intensity:

"kawpow": [
            {
                "index": 0,
                "intensity": 36864,
                "worksize": 256,
                "threads": [-1]
            }
        ],

So you can check that in the OpenCL section of the config. Start with a low number and increase it. The above was for a 580 8gb