Hi!
I’m not sure if your issue is already resolved, but just in case it isn’t: I ran into a similar problem after a system update on Tumbleweed. Steam would launch, but no window would appear — and the start process would loop continuously, stealing focus from other windows and applications.
In my case, the problem turned out to be related to Steam not having proper access to the D-Bus session.
I was able to fix it by editing the desktop entry located at:
~/.local/share/applications/steam.desktop
I replaced the existing Exec= line with the following:
Exec=env -i HOME=$HOME DISPLAY=$DISPLAY XDG_SESSION_TYPE=$XDG_SESSION_TYPE XAUTHORITY=$XAUTHORITY DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS steam
This forces a clean environment while still passing through the essential session variables Steam needs.
I figured this out with the help of a language model, so I might not be able to answer detailed technical questions — but I hope this helps someone else running into the same issue!