Beelink GTi12 + EX Dock, where do I connect monitor

ROM64K

Hello, I have bought a Beelink GTi12 + EX Dock where a GIGABYTE RTX 4090 is installed. Everything works correctly and runs any game at 4k in "ultra" without problems.

But I have a question:

I have tested that I can connect the 144Hz Monitor to both the graphics card and the Beelink. For example, playing COD VI, the performance test shows 2 more fps connecting it to the 4090 than if I connect it to the Beelink.

And the problem I see is that if I want to enter the BIOS, the monitor has to be connected to the Beelink. Connecting it to the 4090, nothing is seen until Windows starts. Also, connected to the 4090, in the Nvidia control panel, the G-Sync option appears and works. On the other hand, when I connect the 4090 to the Beelink directly, the option does not exist in the Nvidia control panel.

I would also like the integrated Iris Xe to run all the tasks that don't require much GPU, and only have the RTX 4090 kick in when extra power is really required.

Can anyone help me with the best way to connect to the monitor and any settings that need to be made in the BIOS?

Thank you very much in advance