You can set a custom URL to use Ollama which is OpenAI API compatible. Llama3 8b runs quite fast for me on a M1 Max. I'll be making use of this feature I think (haven't tried it yet).
It is exposed from Advanced tab under "URL for AI API". You do have to change the model name from the preselected and offered OpenAI GPT model names. Otherwise this AI API URL isn't used. Haven't yet tested with local OAI compatible model yet, though, but did manage to break it using bad address :)
Note that to make use of ollama, you'll have to wait for the next release or upgrade to a beta release --- while you can change the API right now it's using a newer format for the payload, that's fixed in the beta/next release.