I am not sure about the HDMI cable part. Because I use display port and I have no issue getting 10bit colour. 1 thing you have to know. This monitor VX3209-2k only comes with HDMI 1.4 and Display port 1.2. Let me give you an idea, HDMI 1.4 max bandwidth is ~8gigabits/sec . Display port 1.2 can do 17gigabits/sec . So display port is definitely superior compare to HDMI.
By default, this panel is rated for 1440p 60hz . Not 75hz. If you want higher refresh you need to manually overclock it through custom resolutions in Nvidia control panel. However, making it 75hz will get you back to square 8bit colour from 10bit colour.

I see, any planning to buy ugreen dp cable from lazada. Are you able to get 10bit color dropdown from nvidia control panel?
How do you verify it is 10 bpc? thanks.

Yes of course I get 10bit.