I bought a New phone (not a refurb) directly from Amazon (not a 3rd party reseller) that states the phone is unlocked.

I updated the phone with all the latest system and security updates.

I went into Developer mode and then enabled OEM unlocking.

After doing the factory reset and rebooting holding down the volume down button, I get the bootloader but the display says "Device State: locked"

Any suggestions on how I can unlock the phone so I can proceed to the next step of the install?

You missed a step. After enabling OEM unlocking, you need to actually RUN the oem unlock.

After you reboot to bootloader and it says locked, you need to run "fastboot flashing unlock" on your computer (connected by USB), then it will prompt you on the phone to confirm, THEN it will unlock.

    abcZ

    Thank you, that was just what I needed to do. Grateful for the help!
    Solved.