A developer preview of the new Android 12 is available, I installed it on my Pixel 3 XL, and it works fine, a lot of good news on social media too.
Nevertheless this can be worse with DP2 or later, so only do this on a spare phone, and if you know what you are doing.
Android 12 Developer Preview | Android Developers
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First preview of Android 12
Posted by Dave Burke, VP of Engineering Every day, Android apps help billions of people work, play, communicate, and create on a wi...
You can side-load it or unlock your boot loader and use the flash utility.
Downloads for Google Pixel | Android 12 Developer Preview
Instructions for downloading and installing preview system images for Pixel devices
Make sure you have installed the USB driver and start the Android Flash Tool from Chrome. https://flash.android.com/welcome
To lock your phone's boot-loader afterwards, do this:
Install the platform tools from here:
https://developer.android.com/studio/releases/platform-tools
And do this:
adb.exe reboot bootloader
fastboot.exe flashing lock