You don’t have to eat directly after a workout, but 12 hours is pushing the limit.
That said, if you’re getting enough protein in your diet and are making your progress with your training, then it could be fine. So keep track of your workouts and see if your IF plan works with your lifestyle.
Just eat before. If you really feel the need, have something small after. There’s not likely any major difference to consider. Your body will grow if you’re at a caloric surplus. The activity you do over time will influence the composition of that mass. Don’t overthink it.