Perry–
Great to hear you are identifying and address aspects which need attention.
In the beginning it can seem overwhelming, however, as you start chipping away at it you’ll see things start to resolve as position and movement patterns are corrected in other areas.
Spine first, next move to the prime movers hip and shoulder.
Spine, hip, and shoulders set the foundation.

Have 1 focus for upper body, one focus for lower body per day.
If you spend 15:00 or so a day and are consistent yes, you will transition to a proactive, general maintenance work.

As you are more aware of positioning, movement patterns, technique with skills and are seeing lasting change while building a solid foundation you will see some things work themselves out as position/movement patterns improve.
Start chipping away at it.
Have you watched the webinar:
The Athletic Shoulder: Anatomy, Physiology & Function
A place to start with understanding more about how things interact with and within the shoulder.