Yes, that M1 Max should running LLMs really well including 70B with decent context. A M2 won’t be much better. A M3, other than the 400GB/s model, won’t be as good. Since everything but the 400GB/s has had the memory bandwidth cut from the M1/M2 models.
Are you seeing that $2400 at B&H? It was $200 cheaper there a couple of weeks ago. It might be worth it to see if the price goes back down.
That’s why Intel is pitching OneAPI. They want it to be the single API to bring everything together. That’s why it also supports nvidia GPUs, AMD GPUs, CPUs and even FPGA.