Software we use is only available for macOS. Also, Mac mini availability across the world is important. Lastly Mac mini form factor is perfect for the use case.
I suspected so. Excuse my rant, and it's not directed at you, but the software companies only supporting macOS: I never understood that crap. Only offering macOS forces their customers (e.g. you) into the Apple lock-in, eliminating them from choosing the best hardware for the task.
Directed at you: I would try to avoid such software, and look for alternatives. (I expect this to be futile?).
x86 is available across the world as well. Others already pointed out comparable form factors.
Also, computerhardware reliability is pretty good these days. Maybe you could set up a scheme to reuse your tech stack?
On the extreme end, server hardware can run for years with 0 hardware-related downtime (and offers nice things like redundant power supplies, 19" rack cases [but much deeper than audio stuff?]). And brutal performance: Even my 450 Euro used&modified (new nvme disk, faster CPUs), 5y old, 1u(!) Intel dual socket system can mop the floor with most desktops below a Ryzen 3900 (at least on my compile workloads, and on anything that swaps on less than 128GB RAM in general).
