I recently bought a Dell S2721QS 4K monitor that supports 4K at 60Hz. However, when I connect it to my 2016 MacBook Pro 15" running macOS Monterey, I am unable to run it at 4K 60Hz - I can run it at 4K, or I can run it at very low resolutions and 60Hz (for example, non-HiDPI 1440p could be enabled with SwitchResX). I have my monitor connected to my MacBook via a Wavlink WL-UMD502 docking station and a HDMI 2.0 cable. The GPU is the discrete AMD Radeon Pro 450.
The strange thing is, this monitor works out of the box at 4K60 on bootcamped Windows. At some point in the past, I installed Bootcamp Drivers, so I'm not sure if that's helping here or not. Either way, those sort of drivers don't seem to exist for macOS.
I'm not sure if this is a macOS, driver, EDID, or hardware issue. It doesn't seem to be a hardware issue, because it works fine on Windows.
MacOS comes with its own built in native AMD Drivers. Seems like Monterey is a new OS.
Edited my reply because I was showing the wrong Wavlink Model. Found the model at Amazon with its specs: https://www.amazon.com/WAVLINK-Docking-Station-Display-Ethernet/dp/B08PPGYHW1?th=1
Strange but your Wavlink Model doesn't show up at WavLink Website, but it does mention a very recent Driver but for MacOS-X for it: https://www.wavlink.com/en_us/search.html?key=wl-Umd502&type=driver
If you haven't installed this latest Driver for your wavlink Docker that might be the reason why you aren't getting the proper resolutions.
At Amazon it does mention that it supports DP & HDMI 4K@60Hz.
The other Wavlink Docker (UMD-03) that I had posted mentioned that its maximum DP & HDMI was at 4k@30hz and not 60hz
Have you tried to see if you get 4K@60Hz with a different Monitor. It could be not compatible with your new Dell Monitor.
Also since that is a new MacOS it might not be 100% compatible. The Manual shows it being compatible with MacOS-X.
I suggest you open a Wavlink Support ticket and see if the issue is due to not being compatible with Montery OS if the latest Wavlink driver doesn't work.
Found the manual for your Wavlink WL-UMD502: https://manuals.plus/wavlink/usb-c-triple-display-docking-manual#single_display
According to the Resolution spec on HDMI-1 it only supports 4K@30Hz while on HDMI-2 supports 4k@60Hz with DP 1.4.
