Hey @tnk479 , as others in the thread have mentioned, OEM is not the same as Network unlocked. Usually listings will include ''Factory Unlocked'' to indicate that OEM will be available.
Some devices of Pixel can be troublesome (sometimes for no obvious reason) but here are my usual methods to enable OEM.
Method 1. First thing I try is to go to Google's Stock ROM installer and plug the Pixel into a laptop using a Chrome based browser (Chromium, Brave work). Check for an update and see if you see anything relating to ''Verizon or T-Mobile''. This indicates that it is originally from one of these carriers and OEM unlock will not be available no matter what you try.
Method 2. Boot, run through setup, connect to internet (try wifi connection and mobile data too). Update to latest version from within settings. Then check OEM. If it's still greyed out, THEN factory reset, boot, run through setup, connect to wifi and check OEM again. This factory reset after an update can make the OEM become available.
Method 3. Do the same as method 2 and wait a few days, rebooting from time to time but always connecting to wifi. Sometimes a wait time enables the OEM toggle.
If nothing above works then it is almost certain you got a SIM unlocked phone and not a Factory Unlocked phone which enables OEM unlocking.