I bought my ROG SWIFT PG27VQ 165hz Monitor just a little over 12 months ago and a few months in it started doing almost exactly what yours is.
Everry single timme i turn of my PC or unplug the Display Port i get RGBW instead of the monitor going to sleep. It also does the RGBW as its awaiting signal during system startup. I also cannot overclock the panel to 165hz, it wont go higher than 144.
I have searched for any possible solution other than me having to ship off my only monitor for weeks. Also i live in a rural town with no licence to drive myself, so id have to get a courier to pick up and deliver it 500kms away to ASUS in Sydney.
This is a huge inconvenience for me and it makes me sad that due to my situation, i have little choice but to simply put up with the lower refresh rate, flashing RGBW when there is a loss of signal and having to turn the panel off and on at the button every single time. I have always used and encouraged others to buy ASUS products because I trusted in their build quality,performance and reliability. So much so, my current rig that I built 12 months ago has seven ASUS ROG products that were all more expensive than the others, as i had expected.
What i didnt expect however was for these issues with the monitor to start within weeks of it being unboxed. I held out hope that it is something that can be sorted by accessing the factory menu or possibly even a firmware update. I would like to think that anyone selling products with the words "Republic of Gamers" all over them would not want the gamers buying their products to have to spend weeks not being able to game at all because he had to freight his only monitor away for weeks just to have someone press a special combo of buttons and get access to the factory menu and maybe update the firmware. All of which literally takes a matter of minutes to do, and not only is it something that can be done without having to try and post a large fragile expensive piece of technology that weights 10kg, half way across the country.
Please ASUS Tech's, if there is any way at all you can help me with getting this sorted without requiring much more than a few button pushes and a firmware update, then please let me know.
Thanks