[site-packages1]

CopperheadOS is an open source OS that builds on Android and can be used on the Pixel devices. I've found it to be quite secure.

[wolverine876]

Didn't CopperheadOS shut down years ago? The developer, Daniel Micay, now develops GrapheneOS.

[gjsman-1000]

Except for physical attacks. No root of trust means that if your phone was ever stolen, installing a PIN guessing app is easy. Extracting the encrypted data for attacking it elsewhere is also easy.