Other places in the Fediverse:
People have different opinions on how packages should be managed. Of course, there are some package managers which are very similar to each other (DNF and zypper have the same backend), but they can also get really different (Nix/Guix and pacman are basically completely opposite in philosophy). It comes down to preference, and you can’t force anything.
Stick to one of the major distros, not some little-known derivative. Also, please avoid Manjaro, it’s horribly broken, and Ubuntu, because snap. It essentially just comes down to how you want to manage your packages.
Edit: VirtualBox is fully supported on Linux, but QEMU/KVM is better.
I’ve never tried NixOS, but it looks really promising.
I usually use Fedora or OpenSUSE, which have good software availability (unfortunately not as good as the AUR). Fedora provides selinux by default, and has profiles for basically everything. SUSE uses AppArmor, but Arch doesn’t provide convenient configuration for either, and only supports x86_64 (which is why I switched away from it).