Optiplex 7400 all in one with external hdmi input.

My optiplex 7400 all in one when "standalone" works very well with a standard resolution 1920x1080.
When I'm switching to the hdmi input from my geekom IT13 2025 edition (with Intel Iris XE, usually supporting quite powerful resolutions on other monitors) is allowing me a maximum resolution of 1360x768 

Wondering if someone could help me:
1) is this a matter of driver to be installed on the geekom?
2) is this depending by a setting on the optiplex?