No way, by leaving US for long your I485 will be dismissed

even with AP. AP only allow you to leave US for emergency, so not for long. You cannot wait for I-485 outside US. If you go through consulate process, count as a new application. I-485 is for adjustment of status only, so restricted in US.

Also, if you loose or quit your position in US your I-140 doesn't stand anymore, this will also disqualify you for I485.

The ONLY way to wait for I-485 is holding a US position, that is compatible with your I-140. No exception.