Greetings,
I have observed a wrong behaviour that doesn’t happen on the same situation when using DX11 instead of DX12.
When in a blueprint you use the command, for example, r.setres 3840x2160f in a 1080p screen, usually it takes that 4k resolution, render it, but resscaling-adjusting it to the size of the screen (so fonts are smaller, etc). However, if in Project Settings - Platforms - Windows you set Default RHI to DirectX12, it will render that 4k resolution but like windowed, “going out” of the 1080p screen.
Thank you and best regards