On the other hand, outcome-driven fitness (pursuing a goal like "i want to get shredded") never worked for me as well as process-focused.

I have strong legs not because that was a goal, but because I fell in love with cycling and never set ANY goals, just enjoyed getting out and riding my serotonin machine.

That might be more sustainable for some people, but if your interests/hobbies are constantly in flux (which mine are as well to an extent), maybe not. I need to find a way to enjoy the process of sleeping more.