You need to use “Disabled” as a Method for your main Ethernet connection. After that you need to restart the connection. Then test it.
You could also create a second connection for your LAN with IPv6 disabled and leave the first untouched. So you can switch between the two connections.
The Ignored Method will not work, it doesn’t disable IPv6.
Thank you for the answer.
I know there are methods to disable IPv6 by editing scripts and also root commands.
But I don’t want to turn off IPv6 permanently. I want to enable it again when using without a VPN.
That’s why I’m looking for a simple GUI that enable or disable it quickly.
I think I should install NordVPN-bin from AUR so that it can disable IPv6, but it is not Open Source
Then use two connections. One with the standard setting (IPv4+IPv6) for your LAN and a special connection for IPv4 only. You can then switch between the two connections.
You can also create a Ethernet connection with IPv6 disabled and use “Automatically connect to VPN” (not sure if the KDE/Gnome NM settings have this option, but you can do it with nm-connection-editor )
This way you can create a special Ethernet connection that automatically connects to a VPN, with IPv6 disabled. If you don’t need the VPN switch back to your normal Ethernet connection.