Re: BenQ EX3203R Question
There are a few factors that might well be resolved using your settings.
Firstly bandwidth / processing oomph. If you're running 10bits colour at 144MHz you may need a new DP cable which supports the same bandwidth as the monitor. So check what cable you're using for starters Vs the version of Display Port the monitor is using.
Then you can delve into the menus. It's possible that your monitor will support 144MHz only specific circumstances. Bit depth may have to be sacrificed or chroma subsampling may drop to 4,2,2 rather than 4,4,4. It may also drop off HDR for compatibility. It sounds like the monitor probably does have these compromises and is probably in a full on compatibility mode out of the box.
Actually, sod the cable. For starters, is HDR on? It's got poopy compatibility with Windows and will look awful on the desktop unless they've fixed it. Turn that off and see what happens.