Why Can't I Set My 240Hz Monitor Beyond 200Hz?

Have you thought about switching to a DisplayPort cable? That could help you reach the full 240Hz performance. Also, remember that if you’re using FreeSync or Gsync, that could limit your refresh rates based on the FPS you're achieving.

Just a heads up, make sure you’ve adjusted the settings in Windows too. Sometimes the refresh rate needs to be set manually in your display settings.

Double-check your settings. Sometimes the 240Hz option may be considered overclocking on some monitors. My own monitor shows 180Hz, but I can push it to 200Hz with a little tweaking. Also, ensure your PC is outputting the necessary FPS to support 240Hz.

It sounds like you might be running into cable limitations. Make sure you're using at least an HDMI 2.0 cable to support higher refresh rates at 1080p. If it's an older cable, it might not handle 240Hz properly.