I was able to force this on the simulator by modifying the .GlobalPreferences.plist file
If you navigate to your simulator directory
~/Library/Developer/CoreSimulator/Devices/<SIMULATORID>/data/Library/Preferences/
There is a hidden file named .GlobalPreferences.plist
Make a backup of this file and convert it to XML
$ cd ~/Library/Developer/CoreSimulator/Devices/<SIMULATORID>/data/Library/Preferences/
$ cp ./.GlobalPreferences.plist ./.GlobalPreferences.plist.orig
$ plutil -convert xml1 ./.GlobalPreferences.plist
The file should look something like this
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>AppleLanguages</key>
<array>
<string>en</string>
</array>
<key>AppleLocale</key>
<string>en_US</string>
</dict>
</plist>
Add the following inside the <dict></dict> section
<key>SBChamoisWindowingEnabled</key>
<true/>
Then convert back to binary
$ plutil -convert binary1 ./.GlobalPreferences.plist
Now start your simulator and Stage Manager should be enabled
Worked for me on Beta 3 iPad 11 3rd gen sim
Credit goes to
https://twitter.com/KhaosT/status/1533928828753481729
https://itnext.io/you-dont-need-gui-or-how-to-control-ios-simulator-from-command-line-bf5cfa60aed2
