I've never contacted T-Mobile support through Twitter, but I'd like to try asking them to SIM unlock my phone today, for the purpose of enabling the OEM Unlock toggle. How did you guys contact them for this? Did you just DM
@TmobileHelp?
For reference, been a T-Mobile customer in good standing for about 6 years. Just acquired a Pixel 3a from a T-Mobile store on monthly payments, and it is SIM-locked and the bootloader is not unlockable. I would try the factory-reset-without-SIM-inserted method, but I'm on call this weekend and probably shouldn't have my phone out of commission like that :/