Buy ASUS TUF Gaming VG27AQ 27" 2560 x 1440 WQHD 2K Resolution 165Hz 1ms 2xHDMI DisplayPort Adaptive-Sync G-SYNC Compatible Asus Eye Care with Ultra Low-Blue Light & Flicker-Free IPS HDR10 Gaming Monitor with fast shipping and top-rated customer service. Once you know, you Newegg!
The Acer Predator X34 is also G-Sync. I've had one for over a year now and I love it. These are both 120 Hz which is fine for gaming. The newer 1440p ultrawides (2020 models) are now up to 144 Hz but they are all more than $1200 I believe.
EDIT: This LG looks like the one to have right now - its 1440p, 144 Hz, IPS, 1ms response, G-Sync, and its less than $1000 right now...