You're making a lot of assumptions there.

First of all, I don't see how containers are inherently black boxes or a waste of resources. They're a tool to containerize applications, which can be misused as anything else. If you build your own images, they can certainly be lightweight and transparent. They're based on well known and stable Linux primitives.

Secondly, I'm not using containers at all, but VMs. I build my own images, mainly based on Debian. We can argue whether Linux distros are black boxes, but I would posit that NixOS and Guix are even more so due to their esoteric primitives.

Thirdly, I do use NixOS on several machines, and have been trying to setup a Guix system for years now. I have a love/hate relationship with NixOS because when things go wrong—and they do very frequently—the troubleshooting experience is a nightmare, due to the user hostile error messages and poor/misleading/outdated/nonexistent documentation.

By "black box" I was referring to the black magic that powers ZFS. This is partly due to my own lack of familiarity with it, but whenever I've tried to learn more or troubleshoot an issue like the performance degradation I'm experiencing now, I'm met with confusing viewpoints and documentation. So given this, I'm inclined to use simpler tools that I can reasonably understand which have given me less problems over the years.

Ugh, containers/VMs are black boxes because in common practice you just pull the image as-is without bothering to study what's inside, without checking things like outdated dependencies left behind, some dev's forgotten SSH keys, and so on. There are companies that throw the first image they find from who-knows-who into production just because "it should have what I'm looking for"...

Are they knowable? Yes, but in practice they're unknown.

They waste resources because they duplicate storage, consume extra RAM, and so on to keep n common elements separate, without adding any real security, and with plenty of holes punched here and there to make the whole system/infra work.

This is also a terrible thing in human terms, led to a false sense of security. Using full-stack virtualization increases the overhead on x86 even more with no substantial benefit as well.

ZFS has a codebase that's not easy, sure, but using it is dramatically simple. On GNU/Linux the main problem is not being a first-class citizen due to the license and being a port from another OS, not something truly native even though a lot has been done to integrate it. But `zpool create mypool mirror /dev/... /dev/...` is definitely simple, as is `zfs create mypool/myvol` and so on... Compared to mdadm+luks+{pv,vg,lv}* etc. there's no comparison, it's damn easier and clearer.