dalto jrsilvey I was wrong about why I thought the way I did but in the end I still believe that it is best practice to keep GTK and QT as seperate as possible.
One piece of advice I would give you is don't confuse kde/gnome applications with qt/kde applications. Certainly some kde/gnome applications can bring in a huge group of other dependencies but it is not always the case. For example, gnome-disks brings in very little from gnome. The same is true in reverse of an application like krita which brings in very little from kde. It just depends on the application.
I think my brain must have just assumed gnome-disks would bring in a ton of dependencies. Knowing it doesn't will really help me!
jrsilvey WIth flatpaks this is simple.. If you run KDE, install Gnome applications through Flatpak. If you run Gnome/Budgie, install KDE through flatpaks. That prevents pulling dependencies.
Just be aware, you aren't avoiding dependencies this way, the dependencies are just being installed via flatpak. This actually creates more duplication and usage, not less.
The duplication doesn't bother me. I don't mind having additional storage taken up. What I gain by being able to easily remove the dependencies far outweighs what I lose to the space. For instance if anyone installed KMail (which I do not suggest installing after I used it) through Flatpak could easily remove it and all dependencies without them ever mixing with your system files.
After you remove KMail you could then run flatpak remove --unused
which would remove any DE versions that were no longer connected to a a Flatpak App.
In my opinion it is way easier to do that than to do line by line trying to figure out how to remove dependencies.
Having said all of this.. which Desktop Environment do you use @dalto?