Gettning NVIDIA to allow you to set arbitrary modes in xrandr

xorg.conf

# Hacky, only works with startx, tested, october 2022 with  470.57.01

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "Module"
    Load           "dbe"
    Load           "extmod"
    Load           "type1"
    Load           "freetype"
    Load           "glx"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "DP-4"
    VendorName     "Unknown"
    ModelName      "AU Optronics Corporation"
    HorizSync       40.1-275.1
    VertRefresh     40-144.0
    DisplaySize    192 108
    Option         "DPMS"
#PreferredMode "1920x1080_144"
# Adding this gives it a sad.
#ModeLine	"1920x1080_60" 148.35  1920 2008 2052 2200 1080 1084 1089 1125 +hsync -vsync

# WORKS!!
Modeline "1920x1080_144" 368.14 1920 1968 2000 2102 1080 1090 1095 1216 +hsync -vsync

EndSection


Section "Monitor"
    Identifier     "DP-2"
    HorizSync       15.1 - 175.1
    VertRefresh     15.0 - 190
#PreferredMode "nreal_default"
	Modeline        "1920_1080_60" 150 1920 1952 1968 2000 1080 1089 1094 1250 +hsync +vsync
#	ModeLine	"1920x1080_cnl" 148.35  1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync # working
#	ModeLine	"1280x720_cnl"  74.18   1280 1390 1430 1650 720  725  730  750  +hsync +vsync # working
#	ModeLine	"640x480_cnl"   25.17   640  656  752  800  480  490  492  525  -hsync -vsync # not working

EndSection


Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    Option      "UseDisplayDevice" "DP-4"
    Option      "Monitor-DP-2" "DP-2"
    Option      "Monitor-DP-4" "DP-4"
    VendorName     "NVIDIA Corporation"
    BoardName      "NVIDIA GeForce RTX 2070"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "DP-2"
    Monitor        "DP-4"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DP-4"

    Option "HorizSync"   "DP-2: 25-180; DP-4: 25-180"
    Option "VertRefresh" "DP-2: 2-180; DP-4: 2-180"

#    Option         "metamodes" "DP-4: 1920x1080_144 +0+0 {AllowGSYNC=Off}, DP-2: nreal_default +1920+0"
    Option         "metamodes" "DP-2: 1920x1080_60 +1920+0; DP-4: 1920x1080_144 +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"


    Option "UseEDID" "false"
    Option "ModeDebug" "true”
    #Option "ExactModeTimingsDVI" "true"
    #Option "ModeValidation" "NoVesaModes, NoXServerModes, NoPredefinedModes, NoEdidModes, NoUserModes, NoMaxPClkCheck"
    Option "ExactModeTimingsDVI" "true"
    Option "ModeValidation" "NoEdidModes, NoMaxPClkCheck, AllowNonEdidModes"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Also this is another example of setting modes with EDID disabled.