Distrobox to make launchable ubuntu app icon on desktop via configuratoin.nix

Do you know of an example configuration.nix file code chunk, or similar, that
(1) sets up distrobox and
(2) results is a given ubuntu application being available by clicking on an icon in nixOS using Gnome ?

Aim:
I want to have the protonmail proton desktop application Introducing the Proton Mail desktop app | Proton available as one-click on my nixOS device just from the configuration.nix setup (so if I change machine and use the configuratoin.nix the new machine will have the same setup).
https://distrobox.it/

Does this idea even make sense? Of course a properly packaged protonmail desktop app in the nixOS packages would be best.

Does the approach I seek above with distrobox, result in a mess in the nixOS files structure? I only want to do the distrobox approach if it runs automatically under the hood and does not make my tidy nixOS setups into a crazy ubuntu hybrid and I have to manage all sorts of updates and stuff to keep it functioning.

Cheers!

Apparently there is a tool called distrobox-export which might allow for creating desktop entries. But I am not sure how you could just declare those in your configuration.nix.