S2725QS, Framerate does not go above 60Hz at lower resolutions

Using a Windows 10 PC with an NVIDIA graphics card, the monitor works perfectly fine at 4K 120Hz.

For some higher-intensity programs I would prefer to lower the resolution to 1080p while retaining the 120Hz framerate, but nowhere in any Windows or NVIDIA settings could I find an option for this- the highest option for that resolution is 1080p/60Hz.

What can I do to fix this?