EDIT:
Partially solved:
I used the Custom Resolution Utility (CRU) to disable the problematic resolution. Now DSR scales the display to the correct resolution.

However, I'm still interested if the alternative (look for "*") is possible? - since running 50 milion pixels is not really feasable, even on a high-end workstation.

I'm looking for a way to scale resolutions of my 3 monitors 2-times.

Two monitors= 1080p 16:9 | desired-res: 3840x2160
UHD TV [LG]= 2160p 16:9 | desired-res: 7680x4320

What I've tried:

• Custom scaling in NVIDIA control panel
- Works on the monitors, but TV refuses to display the resolution
• DSR Factor in NVIDIA control panel
- Doesn't work properly. Since the highest possible resolution for the TV is 4096x2160, that's what the DSR scales that resolution to (8192x4320) and breaks the 16:9 ratio. Maybe there's a way to disable that resolution?

*An alternative:
I don't need the TV to be scaled, I just need it to "behave" as if it was.
Since I'll use splits for the TV, quarter of the screen will be as big as my other monitors.
Maybe there's a way to scale the size of the display, to behave like it's res is twice as big, without actually scaling the res?

Also, there was a change in beta 20: "Added a physical scaling mode option for monitor configurations". Is this it? Could it help?: (attachment4)

The purpose:

I need the resolution of my main monitor to render at 4K for screen recording, but maintain the functionality of my setup.

Previous topic title: Problem with scaling resolutions on mismatching monitor setup
Attachments:
1.: Current scaled setup that I'm stuck with.
2.: Desired setup in terms of monitor layout.
3.: NVidia control panel DSR resolutions.
4.: Physical scaling update?