Can't get above 60hz DVI-HDMI on my retro pc using an AOC 24G2 monitor

[xenphor]

I have a Windows 98 retro pc setup that I like to use, and I thought having a high frame rate monitor might be nice, since many old pc games use odd ball refresh rates higher than 60hz. I've already been using a cheap Asus VS239H-P monitor with a DVI-HDMI cable attached to a Geforce 4 ti 4600, and it can handle up to 75hz at 800x600 which is decent for older games. The monitor does a decent job scaling the resolution so it's not too blurry.

I was surprised when I used the same DVI-HDMI cable on the AOC 24G2 that it would not go above 60hz, even though refresh rates up to 144hz were available in the display panel. Using VGA did let me select higher refresh rates, but the monitor is very bad at scaling that signal, and even the HDMI scaling is a bit softer compared to the cheap Asus I was using. I'm not that concerned about hitting the max refresh rate of 144hz either; I think up to 85hz would be good enough.

What exactly is going on here?