[Bostonian]

"My thinking was that learning how to navigate and contribute to a large complex codebase would be a good way to self-teach in an attempt to transition to a software development role."

Are you planning to skip the step of writing simple, self-contained programs that solve the kinds of problems posed in textbooks? I would suggest doing that first.

[TheGrkIntrprtr]

I have taken a programming course which included writing a sudoku solver in Racket etc., so I have created that kind of simple self-contained program before. I guess you mean doing the same with C++ specifically?

[Bostonian]

Yes, I think it's better to write some small C++ programs.