i get preplanning big picture architecture or strategy, but i CANNOT plan out the actual code i write. i'm not sure if i just develop deficient mental models of the codebase, but my process for figuring out what to build is to just sit down and build it. my process is very iterative. lots of stubbing things out and working backwards (if i need this function to return an X, it needs args A and B which means it might be better as a method for this class over here...)
the only way i could come up with a precise plan for how the code needs to change is to just build the thing.
Consider this: you could, given enough time. You probably haven't had management that gave you that time. Or demanded you take the time.
Writing things down takes a lot more time than you think. It is hard work. You get better with practice.
You would find, if you were given the time, or permitted yourself to have that time, that you would find all the skills you have accumulated up to this point would converge into that plan. There is a very exciting zen you get into writing things down and you can think about the architecture and the people and the teams involved, and it's a very different thing to create. And very satisfying.
the only way i could come up with a precise plan for how the code needs to change is to just build the thing.