That would make Mint unstable. That is exactly what unstable means in Linux context. There are debian based rolling-release distros, including Debian Sid. This is one of the reasons people choose Arch, because it’s a rolling release you never have to worry about version.
There’s a good chance you might break stuff by upgrading major version like you fear, and that’s why it doesn’t happen automatically. That being said it should be safe, but good on you to prepare backups.


If you’re going to use Arch you should use Arch. One of the biggest advantages for Arch is the AUR which can cause many issues on Arch based distros that are not Arch.
That being said, for a media center, if you’re not used to, I wouldn’t go with Arch, Debian is a much better choice since you’re already used to it and should be good for that use case.