Oh, and some companies offer APIs that match the OpenAI API and there are some open-source projects that do this for llama running locally. Since those would be compatible with the openai python package they will work with magentic too - though some of these do not support function calling.
See for example Anyscale Endpoints https://app.endpoints.anyscale.com/landing
and https://github.com/AmineDiro/cria