Will we get full GTK applications for Librem One?
There won’t be specific Librem One apps like there are on iOS/Android. I think it is better to think of Librem One as service, and what client you use to connect to the service is up to you.
That said, there are a few GTK clients that I think Purism has focused on making adaptive to work seamlessly between the Librem 5 and laptops.
Email - Geary
Matrix - Fractal
Social - Not sure. I think there are some dedicated Mastodon clients around, but I am not sure if they have gotten the adaptive treatment. Alternatively, you can use the GNOME Web/Epiphany browser and access the web version.
VPN - I don’t know about a separate, specific VPN client, but the built-in GNOME settings/menus work for creating a VPN connection
you have tootle