Flexible scaling

Flexible scaling gives you more choices for the apparent size of the desktop interface. BetterDisplay generates scaled resolutions with many small steps between them. These resolutions follow the display's native aspect ratio. The resolution slider lets you move between them.

For the underlying rendering method, see what flexible scaling and custom resolutions change.

For a physical display, use System Configuration and Flexible Scaling. Its settings use system overrides. Editing a value does not activate it. You must follow the Apply and activation steps, including a reboot when required. A virtual screen can instead generate its own resolution list.

These are different paths with different prerequisites. Neither removes macOS or hardware limits, even when the app lets you describe the resolution you want.

See Resolution, Aspect ratio and the system configuration notices. The System Configuration and Flexible Scaling page explains the settings and activation steps.