Edit: I'm an idiot and forgot kinoite is immutable.

Edit 2: Another option after the flatpak that @that_leaflet@lemmy.world mentioned, would be the nix package manager. This would be much more complicated than the flatpak, but if for some reason the flatpak didn't work for you, this is another route you could take.

~~If you want the GUI app, you'll need to add their repo. Instructions are here~~

~~It's a gnome app so you'll end up with some gnome dependencies with it.~~

~~Alternatively you could just use network manager in KDE. You'd need to log in to the protonvpn website and download configuration profile(s) for the connections you want to use and then add them in network manager. After that you should be able to connect from the network system tray icon.~~

~~Finally you could install the wireguard command lime tool with:~~

~~sudo dnf install wireguard-tools~~

~~You'll still need to download (wireguard) configuration files from proton, and then add them to /etc/wireguard.~~

~~Once the configuration files are in the directory you can connect with:~~

~~sudo wg-quick up proton~~

~~Where proton is the name of the configuration file for the connection you want to use.~~