> A function that returns something other than Result has to either call only infallible code or panic on error

...Or solve the problem. A library function that can be a source of issues and can't fix these issues locally should simply not be returning something that is not a result in that paradigm.

> since something can go wrong in most code

That is not my experience. Separating e.g. business logic which can be described cleanly and e.g. API calls which don't is a clear improvement of a codebase.

> the whole codebase converges as time goes to infinity on having Result everywhere.

As I said previously, it is pretty easy to pipe a result value into a function that requires a non-result as input. This means your pure functions don't need to be colored.