Newer macOS is not Unix certified.

It’s UNIX 03 compliant https://en.m.wikipedia.org/wiki/Single_UNIX_Specification

One or two Linux distros were (are?) UNIX certified, though.

If your distro can’t be forked into a “beginner distro” then it’s fundamentally flawed IMHO*.

To be clear, I’ve used Arch as my daily drivers for a while, and while it’s not the best fit for my needs (I use Debian mostly), there’s nothing that I experienced that was incompatible with a “beginner” distro.

You can also drop cache for debugging by running something like echo 3 | sudo tee /proc/sys/vm/drop-caches

But remember that the kernel knows best — this RAM will be automatically be freed up when needed and you should never run this except for debugging (or maybe benchmarking).

WireGuard, and an external HDD. Run at a remote location for off-site backup.

I do this with a raspberry pi 3 at the in-laws. I copied the data over locally before setting it up, and after that it’s just nightly incremental rsync, which is fine even over my slow (35Mbps) upload.

I’m guessing it’s because the developers either have a different speciality that they focus on, are employed to support specific hardware, or both.