I don’t know how this will play out for employment based categories. You need to be have a job and be on a valid visa to even apply for a green card. How do you then go outside the country, apply for a green card, all the while maintaining your job and a visa while you wait for the application to be processed? As far as I know not being in the US for extended periods of time, voids your work visa in the first place.
> You need to be have a job and be on a valid visa to even apply for a green card.
False
You don’t need a job to apply for green card.
Valid visa, yes. But that’s easy.
IANAL. My understanding is that you can do consular processing even if you are in the US, it's just that you need to leave to do the interview (and things like biometrics) and get the actual visa.
Now I'm not sure if you are allowed to re-enter after your interview before your case is decided/you get the visa but I would imagine so (if have valid visa), you would just need to exit again to get the visa later.