With stock and custom ROMs.

  • I’m willing to bet dual-booting will require an unlocked bootloader. There goes your security if this is true.

    You could install GrapheneOS on a Pixel and set up multiple users? Up to 32 if you want. Some can have Google Play Services and some of those can be signed into a Google account while others are just using GP Services without signing in.

    Much faster to switch between users than booting a second OS.