Note that while UMA is great in the sense that they allow LLM models to be run at all, M-series chips aren't faster[1] when the model fits in VRAM.
1: screenshot from[2]: https://www.igorslab.de/wp-content/uploads/2023/06/Apple-M2-ULtra-SoC-Geekbench-5-OpenCL-Compute.jpg
2: https://wccftech.com/apple-m2-ultra-soc-isnt-faster-than-amd-intel-last-year-desktop-cpus-50-slower-than-nvidia-rtx-4080/