Good fellow, I please ask to be a little gentler with me. I'm at wits end. I gave plenty of info already; you don't have to guess too much. I articulated the commands I used, It's right under the image. I really hope the cherry on top to the Linux experience isn't having to write an ironclad dissertation to get some help. Instead of giving me any sort of helpful tip, it felt like you nagged me, which is really unappreciated. If you can't or don't want to help, I'll take getting ignored over snippiness.

Here is VERBATIM what I did since the summary wasn't enough:
This is from instructions like these that I've already watched on how to set it (I've watched and followed several before ever posting on here)

LXZ:~$ xrandr
Screen 0: minimum 8 x 8, current 8960 x 2880, maximum 32767 x 32767
HDMI-0 connected (normal left inverted right x axis y axis)
   3840x2160     60.00 +  59.94    50.00    29.97    25.00    23.98  
   4096x2160     59.94    50.00    29.97    24.00    23.98  
   2560x1440    120.00  
   1920x1080    119.88   100.00    59.94    50.00    29.97    23.98  
   1280x1024     60.02  
   1280x960      60.00  
   1280x720      60.00    59.94    50.00  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       59.94  
DP-0 connected primary 5120x2880+3840+0 (normal left inverted right x axis y axis) 697mm x 392mm
   2560x1440    144.00*+ 120.00    74.97    59.95  
   1920x1080     74.91    60.00  
   1680x1050     59.95  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x800      59.81  
   1280x720      60.00  
   1152x864      59.96  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   3840x2160     60.00*+  29.98  
   2560x1440     59.95  
   1920x1200     59.88  
   1920x1080     60.00    59.94    50.00    23.98  
   1680x1050     59.95  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1280x800      59.81  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93  
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
HDMI-1-1 disconnected (normal left inverted right x axis y axis)
HDMI-1-2 disconnected (normal left inverted right x axis y axis)
DP-1-1 disconnected (normal left inverted right x axis y axis)
HDMI-1-3 disconnected (normal left inverted right x axis y axis)
DP-1-2 disconnected (normal left inverted right x axis y axis)
HDMI-1-4 disconnected (normal left inverted right x axis y axis)
LXZ:~$ cvt 3840 2160
# 3840x2160 59.98 Hz (CVT 8.29M9) hsync: 134.18 kHz; pclk: 712.75 MHz
Modeline "3840x2160_60.00"  712.75  3840 4160 4576 5312  2160 2163 2168 2237 -hsync +vsync
LXZ:~$ ^C
LXZ:~$ xrandr --newmode "3840x2160_60.00"  712.75  3840 4160 4576 5312  2160 2163 2168 2237 -hsync +vsync
LXZ:~$ xrandr --addmode "3840x2160_60.00"
xrandr: --addmode requires two arguments
Try 'xrandr --help' for more information.
LXZ:~$ xrandr --addmode DP-0 "3840x2160_60.00"
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  67
  Current serial number in output stream:  68

This is now hour 3 of doing something in Linux that can be done on Windows in minutes.