I am also fairly new to Windworks/Mystery to Mastery.
What I want to do is encourage you to stick with Greg and Windworks. From skimming your post, I’m fairly certain you have been overworking every aspect of your trumpet playing – as I have been. And, it sounds like you have been employing the Valsalva maneuver (as it relates to trumpet playing) as a substitute for correct technique. Valsalva can be bad for the heart and that’s probably why the medic warned you against trumpet playing. A form of Valsalva is even sometimes used to help patients stop arrhythmia attacks. (https://www.cochrane.org/CD009502/VASC_the-effectiveness-of-the-valsalva-manoeuvre-for-stopping-an-abnormal-heart-rhythm ) Greg’s method teaches people how to play without Valsalva.
Please stick with Greg’s teachings. I believe you will find yourself playing more easily and at a higher level of accomplishment than ever before. Like you, I am struggling to get past decades of deeply ingrained techniques and habits. It only takes one breakthrough to start to change everything. One changed enough of how I play so that I can finally see my way to not only regaining all my past ability but surpassing it — using Greg’s methods.
Hang in there and wait for your breakthroughs to begin to happen. Everything will start to change when you get there.