It doesn’t exist. You can’t find everything you want from an app, it’s like finding a unicorn. You’re going to have to compromise in some areas to get something you’re happy with. These are all things I have heard said, or have been said to me when I have been looking for the perfect app previously. It doesn’t matter if it is a todo app, calendar app, or note-taking companion - the perfect thing just doesn’t seem to exist. Doesn’t stop me from looking though!
Every once in a long while an app will feel perfect, but there's always something that could be better. Maybe it's a tiny thing you could do in one step instead of three, or maybe it's a design choice you don't totally love. I've discussed the concept of "forever apps" myself, but even in those, there are things I would change.