"Package" to run script as root?

Is there a way of creating a .deb file that can be loaded via the GUI that will do nothing except execute a script as root?

With ReadyCloud being terminated, I have recommended ZeroTier as an alternative.  But that package can no longer be installed via the GUI because one must accept a non-secure source.  But a lot of users aren't comfortable using SSH.  Since it can be installed from SSH, I believe a script run as root could as well.  So, I'd like to create one, if that's possible.

Yes, some settings could still only be performed via SSH, but the documentation indicates that creating a <NetworkID>.conf and <NetworkID>.local.conf in /var/lib/zerotier-one/networks.d/ will cause ZeroTier to join <NetworkID> at start-up, and that's the only thing one really needs to configure.