M1 macs tend to have issues with custom resolutions. Notoriously they don't allow sub-4K resolution displays to have HiDPI ("Retina") resolutions even though (for example) a 24" QHD 1440p display would greatly benefit from having an 1920x1080 HiDPI "Retina" mode. To fix this issue, some resort to buying a 4K HDMI dummy dongle to fool macOS into thinking that a 4K display is connected and then mirror the contents of this dummy display to their actual monitor in order to have HiDPI resolutions available. Others use the built in screens of their MacBooks to mirror to the external display. These approaches have obvious drawbacks and cannot solve all problems. To fix this problem, BetterDummy creates a virtual dummy display which you can then utilize as a mirror main. Advantages of BetterDummy over a physical 4K HDMI dummy plug or mirroring your internal display: - Your HDMI port will remain usable for an other display on the Mac Mini. - Your internal screen will be available as an extended space on a MacBook (or you can use clamshell mode). - Does not suffer from issues that prevalent with the physical dummy (like jittery mouse cursor). - Offers a much wider variety of HiDPI and standard resolutions. Works with all aspect ratios, does not depend on what resoluations are recorded in the dummy's EDID/firmware. -Does not utilize graphics hardware in vain so it is somewhat faster. Available instantly. - It is free (but donations are super welcome)! :) Some other possible uses: - The app is also useful for anybody who is not satisfied with the offered default HiDPI resolutions offered by macOS - as in some cases this could be rather limiting - especially on Wide or UltraWide displays. - Use headless Macs (servers) with any resolution and HiDPI mode for remote access (tested on Intel Mac with Intel UHD 630 - please note that the app runs in user space after login). - Scale Sidecar resolutions. - Better quality zooming (System Preferences»Accessibility»Zoom) or High Quality screenshots even on Full HD displays. Hope you like it!