I have some interesting news: I found a solution to enable HiDPI on M1 based Macs on any resolution, even on 1080p screens, without the need to use mirroring or other workarounds.
Here is an example of HiDPI running on a Dell U2415 monitor that only supports a maximum resolution of 1920x1200:
What you need to do is to edit the com.apple.windowserver.displays.plist file located in
/Library/Preferences/com.apple.windowserver.displays.plist
and change the key <key>Scale</key>
to have a value of 2.
This is an example of how the section in the displays plist file should look like after the change:
<key>CurrentInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1200</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>1920</real>
</dict>
Make sure that you change only the Scale key for the monitor that you need, and nothing else.
You can follow the step-by-step video tutorial on how to make the changes in the displays plist file here:
https://www.youtube.com/watch?v=Z1EqH3fd0V4
After that, restart your Mac and you should get HiDPI and noticeably more crisp and anti-aliased text, and the high resolution macOS icons.
An easy way to confirm that the HiDPI changes work is by looking at the Safari icon on the dock. If the HiDPI version of the icon is enabled, it will have a lot more sections in the compass than the low resolution icon. It should look something like this:
Please note that while this might make the image look better even on 1080p screens, they will still be running at 1080p resolution, so the change might not be as drastic as running on a higher resolution screen.
If you have any questions about the procedure, please feel free to contact me or comment below.
I'm facing the same issue. Please fix this ASAP.
As a reminder to everyone who is unhappy about the current situation with HiDPI and does not want to use BetterDummy: Apple is not watching this thread. They never will. The only way to reach them is to contact them via the Apple feedback form Apple Feedback form According to the Apple Care Senior person who I talked to in the last days this is the only metric that is actively monitored/watched to improve their products. The form literally takes one minute to fill out. Thank you all!
i feedback to the support team but no one answers me about this problem. mac os 12.2 released but still i have screen flickering, low quality screen only because i use apple silicon chip. why me and many others must have bad experience but apple and support don't care about it. the only solution is not let this topic get down. we should tell them every day that we have problem. that's the difference between apple products and pc!!!!!!!!!!!!!!