It is important to read carefully, but there is an error of detail about Android 11.
This is the critical warning
It is important that you know that downgrading Smartphones on OS versions greater than the /e/OS OS version you plan to install, can cause instability or at worst brick some devices. We recommend that you check your current OS version, before attempting the installation.
The download location https://images.ecloud.global/dev/barbet/
does offer /e/OS available in Android 11 R and 12 S
Please check the following link to see the naming convention used by /e/ Android version
The Android R versions are now dated. So you will want to first downgrade your Pixel to Android 12 and then install e-1.12.3-s-20230616300623-dev-barbet.zip.
Downgrade of Android OS on Pixel is made easier than some other brands. Check out
or mentioned here more privacy friendly