The ViewSonic Elite Xg270Q gaming monitor is an excellent product capable of offering very good image quality, fast refresh rate, Adaptive Sync and excellent performance at 1440p QHD resolution. This monitor is currently sold on Amazon US for only $418 and it the lowest it has been for almost a year now.
The monitor comes with IPS 27-inch screen, 165hz maximum refresh rate, 1ms fastest response time, 16:9 aspect ratio, 2560 x 1440 QHD resolution, Adaptive Sync with NVIDIA G-Sync certification, VESA DisplayHDR 400, Elite RGB on its back, metal base, built-in mouse anchor, headphone hook, complete ergonomics that will let gamers adjust the screen just as they want it.
ViewSonic advertises the monitor as being NVIDIA G-Sync compatible, but the monitor surely supports AMD FreeSync as well, so you should be safe using it with AMD GPUs too without worrying about its performance. The monitor is currently available on Amazon for only $418, which is almost $100 cheaper than a few months back.
If you need a gaming monitor that is capable of delivering great performance at 165hz and 1440p resolution, then this Elite XG270Q should do it. Please note that in order to get the best out of it you will need to pair it with an NVIDIA RTX 3060 or higher numbered models in order to to high FPS values at QHD resolutions.