Hello, I use a 3440 * 1440 screen in 60 Hz as well as a UHD screen (3840 x 2160) in 60 Hz without any problem.
The Samsung Odyssey G9 uses 5120 x 1440 up to 240 Hz, which is probably not supported by this dock. You'd be better off buying a thunderbolt 4 dock.

To confirm this from our side. You will need a more powerful docking station to really be able to operate the G9, especially to utilise its full potential.

Not familiar with Samsung Odyssey G9.

No idea, don't know the device. My notebook runs great with it.