Sounds like you would benefit from a morning and afternoon/evening session.
Spine first so you’ll want to start addressing your sitting position.
If your spine is not in a good position you will see restrictions at the prime engines of the shoulder and hip.
Improving this will help your shoulder be in an improved position.
I’d recommend watching this webinar to get a better understanding of how the shoulder works.
The Athletic Shoulder: Anatomy, Physiology & Function

Make a plan and work the plan. Be consistent. It may seem like alot start chipping away at it. As somethings improve you may see other items improve as well.

Pro Episode # 9 – Spinal Archetypes

You want to keep a session to a max of 3 items.
Quality over quantity.
The test retest will vary depending on what you are addressing.
Some episodes give a test/retest.
Some to start with

Is the pain in your shoulders when training from rolled forward positioning?
Episode 261: Perfect Pushup ER Lie Detector
Episode 178: Flexion + External Rotation Analogs
Episode 175: Improving Shoulder Positioning for the Press and Rack
Episode 166: Ninja Recovery and Some Shoulder & Hip Love
Episode 80: Best Shoulder Mob Ever
Episode 41: Improving Shoulder Organization & 3 min Challenge

Standing position
Torque and Trunk Stability Part 1: How to Stand
Episode 274: The Standing Athlete

Sitting