Your experience sounds rough.
My experience: I often thought that I didn't have the time to learn (hard) things, only to find out sooner or later that I actually did, and still do.
At work, this usually meant that I was giving myself tighter deadlines than they needed to be, or that I was putting too much effort into tasks nobody cared that much about. Over time, I learned that it's OK not to put 100% of energy into the assigned task. Sometimes, it's even encouraged to use that extra energy to learn.
Arguably, I did have the privilege of starting out in salaried European office jobs, where there are more robust boundaries and opportunities. It's obvious how precarious physical work discourages this kind of learning. And reading comments like yours, it's clear how lucky I was to have managers and environments that didn't exploit my eagerness to put pressure on myself.
But if you do have an opportunity to make adjustments, I'd suggest putting less pressure on performing like an athlete, and channeling that energy into learning opportunities instead. Rarely will anyone carve out time for your learning, but they may be responsive to your request or boundaries.