What do you do when baby flips one way and not the other?

4.5 month old. Can flip back to belly, not belly to back. Constantly is flipping over in crib and screams bloody murder every time and absolutely hates sleeping on belly. What do you do in this case? It’s not feasible for me to go in every single time since it happens about every hour in the night. Plus naps have gone to shit because it also happens for naps. They’re max 30 minutes if baby is on belly. Helppppppp 🆘