Question: I have an early morning work shift. Is it better to daven shacharis alone before I go, or to daven afterwards with a minyan?
Answer: The Shulchan Aruch (OC 89:3) writes that one mustn’t work or travel before one has davened. This applies from alos hashachar, dawn, when one can begin davening. As one cannot daven before alos hashachar, one may work then. The Mishna Berura (89:37) writes that if one is going to work within half an hour of alos hashachar, they should say birchos hashachar beforehand (See Rema 89:3; Biur Halacha 70:5).
The Mishna Berura (70:23) writes that if one begins working before alos hashachar they may continue working until afterwards providing that they ensure that they say shema and daven before it’s too late.
The Mishna Berura (89:20) and R’ Ephraim Greenblatt (Rivevos Ephraim 1:66) write that one must daven before one goes to work even if that means that now they have to daven without a minyan whereas later they would be able to daven properly with one.
In conclusion, if one is going to work before alos hashachar, they should say birchos hashachar first and daven later.
One who goes to work after alos hashachar must daven first, even if that means foregoing the minyan. Ideally, they should still go to shul after work to hear kaddish, etc.