Just nitpicking: unlockable bootloaders. The bootloader is locked by default. But you can unlock it without needing Google.
Additionally, Pixels support a Linux VM and has a desktop mode (I'm running GrapheneOS, it may still be that these features have to be enabled through the developer settings).
And even with this there are still apps which require hardware attestation and won't work on alternative operating systems.
> But you can unlock it without needing Google.
Well akshually.... the bootloader is initially not unlockable. You must connect the phone to the internet. Within a few minutes a background process will reach out to Google servers to check whether it was purchased outright or with a payment plan. It will only enable the bootloader unlocking toggle after this step. Phones bought with a carrier contract won't be unlockable until paid off.
In those initial few minutes (/ before you connect it to the interwebs), the bootloader unlock option in the developer settings & fastboot will be disabled.