Delaney If you're going to buy a Pixel device from Amazon, make absolutely sure OEM Unlocking is able to be enabled by the user. Users buying supposedly 'unlocked' Pixel 6a phones from Amazon have had trouble installing GrapheneOS: https://discuss.grapheneos.org/d/4467-oem-unlock-grayed-out
Note that in the case of the Pixel 6a, this might be due to the stock firmware being older than June 2022, and can be fixed by updating the phone. Personally, I bought my Pixel 6a from the Google Store and I was able to unlock it from the get-go without updating the firmware.
Pixel phones which are locked to a certain carrier tend to also prevent users from unlocking the bootloader, but that doesn't mean an 'Unlocked' phone will allow the user to unlock the bootloader, too. The only phones I know for certain allow unlocking are the ones sold from the Google Store, but there are likely brick-and-mortar stores which sell Pixel phones like this too (in my country, options are more limited).