Here's a good range of model sizes that run just fine with llama.cpp on mac: https://huggingface.co/telosnex/fllama/tree/main.
I recommend trying the Telosnex* app, it uses llama.cpp and abstracts over LLMs so you can i.e. switch between local/servers at will.
The important part for you is its free, accelerated on macOS, and very easy to use local LLMs with (Settings > AI > LLM > On Device, tap Get)
Prepare to be underwhelmed, slightly: its only when you start hitting 3B that its coherent, anything under that will feel more like a markov chain than an LLM.
Depending on how geeked out you'll be to have it running locally, you might have fun with that Telosnex can run local models on every platform, i.e. you can run local models on iOS/Android/web too.
* because it's mine :3 It is quietly released currently. I want to get one more major update before widely announcing it in Jan 2025