This blog post really captures the core of where null checking should go and how to capture that you've already vetted this field for correctness in the type system so that the rest of your code never has to worry about it -- and further, cannot because the types don't allow!: https://lexi-lambda.github.io/blog/2019/11/05/parse-don-t-va...

This is echoed in an amazing book called Domain Design Made Functional, which radically changed how I thought about what a type system is and what it can actually do for us if we lean on it correctly (even a relatively crummy one like Java's!).