Redundancy is not a good use of focus for most people (except SREs and the like). The whole point of redundancy is to remove something from focus. I'm guessing you checked everything by hand for the sole purpose of not having to focus on these calculations mid-flight. I'm sure most commercial pilots rely on a larger organization to make these checks for them and their organization probably employs its own system of checks and redundancies at scale. Putting that all on the pilot is not going to give you a sustainable transportation business.

If you're just trying to get off Gilligan's island, that's another thing entirely.