Pixel 4a OEM unlocking disabled

So I got a used Pixel 4a because I wanted to put a custom OS on it as a burner phone when traveling in case it gets stolen but OEM unlocking is disabled.

I tried to sideload the OTA verizon update but it complains that it's older than the current build and won't allow me to install it.

Factory resetting doesn't change the build either which I foolishly thought it would put it back to whatever it originally came installed with.

Is it at all possible to enable OEM unlocking or am I stuck with it like this for good?