Yes it’s easy, install WireGuard in a container, port forward to it and copy the profile to your other devices.
When you connect to the WireGuard network on the second device, you’ll have access to your internal network and hence your nas.
I also use a reverse proxy so I can remember computer names rather than ip.
Snap is a sandboxed environment to install applications in.
Flatpak is a more portable implementation of the same broad idea, it downloads a chroot and runs applications from within using a separate program called bubblewrap (one could, in theory, use chroot to run apps from within the downloaded flatpak images, bubblewrap offers further isolation through things like namespaces and cgroups etc. )
Snap, unlike flatpak, is a Canonical specific implementation that has a reputation for breaking a lot of things.