One question about your functional point: where can I learn functional programming in terms of organization of large codebases?

Perhaps it is because DDD books and the like usually have strong object oriented biases, but whenever I read about functional programming patterns I’m never clear on how to go from exercise stuff to something that can work in a real world monolith for example.

And to be clear I’m not saying functional programming is worse at that, simply that I have not been able to find information on the subject as easily.