Google hardware actually gives you the most freedom, no other Android phone allows you to install a custom operating system, relock the bootloader and use Android Verified Boot, which is a fundamental part of the Android security model, with a custom signing key defined by the custom OS. It also includes the Titan M2 secure element which gives you great security through features like Android StrongBox, the Weaver API and it even has Insider Attack Resistance meaning Google, even if they get a court order to do so, can't comprise the Titan M. Firmware can only be loaded to the chip after proper user authentication. Yes, it's a little ironic, but Google hardware gives you the most freedom over your device.

I mean, you do unfortunately. Other hardware manufacturers have their phones locked down so hard the GrapheneOS devs won't even touch them.