If you're writing true low-level code then you're most likely doing it for performance reasons, like ffmpeg. But ARM doesn't have the instruction set to make the best use of that, x86 does with its extensions. Otherwise, the compiler handles translation, so there's just no reason for you to care about the assembly unless you're writing assembly.

As for nice laptops, I think Asus and Lenovo makes some nice ones. I don't believe any are fanless, but most are quiet - Lunar Lake gen 3 is an SOC with a base TDP of 25 watts, and it can even go down to 15 watts. These CPUs are slightly faster in multi-core performance than M4, and they use similar wattage. I believe the Asus zenbook duo gets better battery life by a wide margin because of the 99 watt-hour battery. They still fall a little short of M5 in performance, but it's very close.

As for servers, it's a good point. But I think currently most servers are still using x86 CPUs, so it might not be relevant for a while.