You don't need to mess with the registry settings.
You can change the output settings via MPC-HC, which also change exact same registry values.
Also you can change the registry just by typing in windows search regedit or whatever similar to regedit.exe
Also lel you when you set this "VPSuperResolution"=dword:00000003
to 3, you set it back to 1080p or lower.
What was the point of setting it to 1440p at first, and then changing via registry it back to 1080p?