AIO as external Monitor stuck at 768p

Hi guys, I have an OptiPlex 7470 AIO and I want to use it as external monitor.

Equipment tested:

OptiPlex 7470 AIO - i5 9500, 1080p screen, Dell OSD installed

Dell WD19 Docking Station, 180w adapter, HDMI cable (which definitely can output 1080p)

laptops tested:

- Latitude 5290 2in1 - i5 8350U

- Latitude 7430 - i5 1245U (main)

- Latitude 3550 - i7 1355U

So far, only 5290 can output 1080p into the AIO, while both 7430 and 3550 are stuck at 768p.

I'm pretty sure that no hardware is faulty or bottlenecking the resolution output.

Is there a solution to this?