I think you need to use Wayland, focus stealing protection set to strict, and no Xwayland apps. Xwayland apps can bypass the focus stealing protection.
Gnome
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Also incorrect. Wayland apps still steal focus.
As far as I’m aware, Wayland apps can only “steal” focus by going through the proper channel, the xdg activation protocol.
Or maybe it’s a bug with Gnome 43?
That's still stealing focus. I want it to literally never happen.
And it doesn't do it properly for me either. Starting from the command line with a delay (how I test it) still steals focus when I'm focused on a completely different application.
Did you set focus stealing protection to strict? And verify the applikation isn't running through xwayland?
Yes. Should I restart my shell? Disable Xwayland temporarily