I'm posting an article I found which hasn't been mentioned here before because it seems well-researched and brings awareness to a topic directly related to installing GrapheneOS.

Here is the article: https://www.fitzsim.org/blog/?p=545

Excerpts:

None of the many many YouTube videos I watched about bootloader unlocking covered whether or not you need Internet connectivity. Nor did any of Google’s official documentation. GrapheneOS documentation is the only place on the Internet that documents this requirement, so, well done GrapheneOS documentation team!

I thought (based on the aforementioned GrapheneOS docs) that the device model variant I bought, being sold “unlocked”7 by Google, would not need the Internet connection. NOPE; Google sold it to me with “OEM unlocking” greyed out:

I consider this a customer-hostile practice. I should not have to connect a piece of hardware to the Internet, even once, to use all of its features. If I hadn’t connected the Pixel 7 Pro to the Internet, then “OEM unlocking” would have stayed greyed out, thus I would not have been able to unlock the bootloader, thus I would not have been able to install GrapheneOS.

Request to Google: ungrey the “OEM unlocking” toggle in the factory, before shipping store.google.com devices to customers. Do not make your customers connect the device to the Internet before they are allowed to install the operating system they want.

Google should not restrict its users by forcing them to check-in with over a dozen of their endpoints before they can use the phone that was sold to them for their own purposes.