Created attachment 153167 [details]
Xorg log

SUMMARY
When attemptng to configure KDE to use a higher refresh rate (such as 120Hz), it results in no behavior. I confirmed that the graphics card (AMD Radeon Rx 590) in combination with the monitor (Gigabyte M32U) is capable at running 3840x2160@120Hz.

STEPS TO REPRODUCE
1. Open Display Configuration
2. Confirm that resolution is configured to max resolution: 3840x2160
3. Select 120Hz from the list of Refresh Rates

OBSERVED RESULT
Nothing occurs. The newly selected refresh rate is still indicated but no change in the display actually occurs. When exiting this particular module then re-entering it, the Refresh Rate selected item is now reverted to the original However, switching between lower refresh rates such as 98Hz to 60Hz (or vice versa), results in expected behavior: the monitor would flicker then a Dialog box appears giving the user the option to keep the new settings or revert to the older settings. 

EXPECTED RESULT
I expected the display to reset at the new desired refresh rate. 

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.26.1
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6
Kernel Version: 6.0.2-zen1-1-zen (* I tested this as well on a vanilla unpatched kernel from versions 5.19 onwards)

ADDITIONAL INFORMATION
Several items of note:
1. Attempts to change the refresh rate via `xrandr` does result in an error: 

```
$ xrandr --output DisplayPort-0 --mode "3840x2160" --rate 120
xrandr: Configure crtc 0 failed
```

I should also note that the monitor does reset. 

Here is the output of `xrandr --properties` in the relevant parts:

```
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
        EDID:
                00ffffffffffff001c540432fe090000
                231f0104b54627783be1b5ad5045a025
                0d5054bfcf00814081809500714f81c0
                b300d1c001014dd000a0f0703e803020
                3500b9882100001a000000ff00323133
                3531423030323535380a000000fd0030
                90ffff83010a202020202020000000fc
                004769676162797465204d3332550212
                020342f156010304131f120211900f0e
                1d1e60610514765d5e5f2f2309070783
                01000065030c0010006d1a0000020b30
                900005653c653ce305c301e606050165
                6512565e00a0a0a0295030203500b988
                2100001a8a6f80a0703840403020280c
                b9882100001a6fc200a0a0a055503020
                3500b9882100001a0000000000000035
                701279000003016447f80104ff0e4f00
                07001f006f087e0070000700eba30104
                ff0e4f0007001f006f087e0070000700
                d0500104ff0e9f0010003e006f082700
                14000700fb7e00047f07870017001f00
                3704110002000400f7e30004ff099f00
                07001f009f0531001800070000000000
                0000000000000000000000000000d190
        GAMMA_LUT_SIZE: 4096
                range: (0, -1)
        DEGAMMA_LUT_SIZE: 4096
                range: (0, -1)
        GAMMA_LUT: 0
                range: (0, 65535)
        CTM: 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0
                0 1
        DEGAMMA_LUT: 0
                range: (0, 65535)
        TearFree: on
                supported: off, on, auto
        subconnector: Native
                supported: Unknown, VGA, DVI-D, HDMI, DP, Wireless, Native
        vrr_capable: 1
                range: (0, 1)
        max bpc: 8
                range: (8, 16)
        underscan vborder: 0
                range: (0, 128)
        underscan hborder: 0
                range: (0, 128)
        underscan: off
                supported: off, on, auto
        scaling mode: None
                supported: None, Full, Center, Full aspect
        link-status: Good
                supported: Good, Bad
        CONNECTOR_ID: 65
                supported: 65
        non-desktop: 0
                range: (0, 1)
   3840x2160     60.00 + 144.00   120.02    96.01    72.02    60.01    50.00    48.01   120.00   119.88   119.91    97.98*   60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98
   2560x1440    144.00   120.00    59.95
   1920x1200     60.00
   1920x1080    144.00   120.00    60.00    60.00    50.00    59.94
   1600x1200     60.00
   1680x1050     59.95
   1280x1024     75.02    60.02
   1440x900      59.89
   1280x960      60.00
   1280x800      60.00
   1152x864      75.00
   1280x720     120.00   119.88    60.00    50.00    59.94
   1440x576      50.00
   1024x768      75.03    70.07    60.00
   1440x480      60.00    59.94
   800x600       72.19    75.00    60.32    56.25
   720x576       50.00
   720x480       60.00    59.94
   640x480       75.00    72.81    66.67    60.00    59.94
   720x400       70.08
```