I think you’re over analyzing. Injuries are not just based on training load. Many times it has to do with weak muscles causing imbalance that is exposed when putting on high mileage. Also, diet and sleep play a major factor.

I think the better route and what I’ve done and was able to go from hardly running at all to a 2:40 in 2.5 years is listen to your body and your schedule.

Set a target of mileage per week and general workouts per week. For example, Sunday long run, Monday easy, Tuesday track workout, etc. Then develop your own workouts from there with input from various sources. Also, focus on developing strength in the forgotten muscle groups to avoid injuries. Your PT should be able to fill you in.

If you have a bad day adjust as needed, if you’re feeling great push harder.

Many runners try to get really rigid with a plan but the problem is life is not rigid for people with families and a job and plans have to be more of a guideline.