I have been reading the manual for your monitor..
You will need to use the display port cable to get 144hz, HDMI only goes to 60Hz..
From what i can see, you should have a disc for the monitor with the monitor driver on it.. It does say you will need the driver installed..
Also from the manual, you may have to use the OSD on the monitor to set to DP and overclock to a higher refresh rate..
Personally i would leave it at 144Hz and not OC..
AOC AG271QG 27 inch monitor | AOC Monitors | AOC Monitors
AMD Ryzen 7 3700x, Asus Tuf Gaming RX 6700 XT, Asus TUF Gaming x570 Plus, 32gb G.Skill TZ neo 3600mhz, Samsung 980pro 1tb NVME, Samsung 970 EVO Plus 1tb NVME, Lian Li Galahad AIO 240mm, Antec Titanium 1kw.