The marketing seems to assume your customer are knowledgeable athletes who want an app to track their performance. I would introduce two more user personas. The first is the type whose New Year resolution is either to lose weight or build stamina. Your app should suggest a program like a personal fitness trainer, show them what to do, and track their progress and give them encouragement when they achieve some milestone. The second user has a specific goal but need help coming up with a realistic training plan For example, they want to pass the new Army fitness standards.
https://armypubs.army.mil/pub/eforms/DR_a/ARN35762-DA_FORM_7...
You wouldn't know it from the website (working on that!), but the app experience is more for "fit people who want to optimize their fitness and like to analyze their training data".
It's just been a tough nut to crack to find the right way to express that so far, but to the point of this thread and all of this dialogue, that's also key to the unlock.
I'm a former military guy myself, and I've been thinking about cloning + rebranding a version of the app that's super specific to "Training for military fitness tests". The more I think about that, the more I think there really might be something there.
Reasoning:
It _seems_ like if you make the programs legitimately useful and look reputable, not only would you get the people looking to pass a test in the actual military (which may be relatively few? I have no idea), but I bet you'd _also_ attract a ton of CrossFit or other fitness buffs who just want that "authentic" functional training feel: "Look at me according to this app used by legit military trainees I'm so fit I can be in the MilitaryBranchX!"