Finally decided to give GrapheneOS a try as I've got a fp6 with /e/os and love it.
Found an eBay listing for one in very good condition, and right in the subject it says unlocked. Got it yesterday, excited to try it. Start following the install instructions, only to see OEM unlock grayed out. One article says, it must be connected to the internet, so I connect it to wifi. Still grayed out. Another article says install all the updates and reboot. Two hours later, still grayed out. I've measaged the seller asking for a refund, but I don't know. Anyone else have an idea?
Like I said, OEM unlocking is grayed out. Everything I tried didn't work.
Gotcha. didn't realize you meant the developer settings options was greyed out since your pic was just off the bootloader.
There are two possibilities here:
it needs to check in over the internet to enable OEM unlocking. Boot into the OS, connect to Wi-Fi, then do a factory reset from within the OS. Go through setup a second time then and it might enable OEM unlocking.
The device was not purchased fully and may have been on a payment plan. You can try contacting the various carriers and providing the IMEI to them and ask if the device appears in their inventory as still needing to be paid off. You might be able to convince them to unlock it for you.
Here is a reddit thread with some information that might help. Read all the comments. Several people have been able to get around this with different approaches (trying sim cards from other carriers, telling the carrier you're an android developer, etc): https://www.reddit.com/r/GooglePixel/comments/sc2w1r/fyi_if_your_oem_unlock_is_greyed_out_after/
Good luck! You might just have to return it but it's worth a try.