Question about AsRock Z390 Pro4

Dear Digitec Team You write on your homepage that this board has a DisplayPort 1.20. I also need this to operate my monitor (EIZO SX2762W with 2560x1440). Unfortunately, this is not the case and my screen now only runs at 1920 x 1200! Unfortunately, that's all I can do. The control for the graphics does not allow a higher resolution even on the HDMI port and the picture looks Sch...... What do I do now? Please find a solution...