A few adjustments in OSD Setup & Calibration might help colors seeming washed out,.. the PG27UQ is a 120Hz monitor, when you engage the overclock, it will run reliably at 144Hz, but it will only do this with a YCbCr signal. If you want to stay in the RGB realm, you have to run at 120Hz for 8-bit signals and 98Hz for 10-bit.
There are also small gains to be had when adjusting the RGB sliders. And in the Image menu features you have two levels of overdrive, dark boost to increase shadow detail, auto black level, which I leave OFF, and aspect control. For both SDR and HDR material turn ON Variable Backlight, when turned on, it tracks gamma correctly and improves black levels enormously. Generally Calibrating is unnecessary if you choose Racing mode for SDR content, and for maximum contrast, set the Variable Backlight to Fast.
See if adjusting any of those settings help, that's basically the only calibration options I have adjusted on my monitor, and I'm no expert.
Good luck, it takes a lot of trial and error adjusting all the options finding out exactly what the effects are, trust me I have used the All Reset, returning all settings to factory a few times. 😄