If you’re using a Debian based distro, you can search through contents of packages to see if there’s a conflict:

E.g. apt-file search /usr/bin/sh

KDE Neon: https://neon.kde.org/ , straight from KDE devs.

You’re missing the point.

Bash is the ducktape of programming languages.

You could read the docs.

What you’re proposing is creating a Frankendebian, which Debian explicitly warns against doing. The proper way of getting security patches from unstable would be to pull the source debs and compile it yourself against the current Debian testing base.

This lane of thinking however seems to be completely misguided when it comes to the target audience here, that is, a user who is not even experienced with Linux in general enough to know about various rolling release distros. Telling a user this inexperienced to go with either of those is in bad taste at the very least.

Just keep in mind that you will not be receiving speedy security updates, and in some cases you will need to wait for quite a while before packages you have will be updated (weeks, maybe longer).

If you want a proper rolling release distro that is not Arch/Gentoo/Void/Nix/GuixSD, you could go for openSUSE, which provides a rolling release distro with a system rollback feature by default. Nice, easy to use GUIs for whatever you need. Although openSUSE also is sometimes a bit slow with the security updates for some packages, it’s nowhere near as slow as Debian testing.

What you’re trying to use is “hardware” RAID. Using hardware RAID is generally a bad idea. If you’re using Linux, use software RAID instead.

Also consider using Btrfs, it will make having a RAID setup even easier.