What I meant I had the issue with on my pixel 4a was not the boot loader but OEM locked

“Next, go to Settings > System > Developer options and toggle on the OEM unlocking setting. On device model variants (SKUs) which support being sold as locked devices by carriers, enabling OEM unlocking requires internet access so that the stock OS can check if the device was sold as locked by a carrier.” Most of those 4a phones were sold as locked by carrier. 

 @SuckMyDick @Autodidact Most carriers don't lock the devices they sell. It's mainly an issue in the US. 

 Yes I am in the us, I think I had a Verizon phone I bought on eBay. It’s important to check before buying