There may be some people for which my advice is bad.

But otherwise, these are lessons. If you don't focus, and so get nothing done, you'll learn to focus, by saying no to some things, even if everyone tells you they're critical.

Conversely, if you focus too much on one thing, do it excellently, and fail at other things, which I've done, I've learnt to do things to the extent needed, not more, as opposed to building a car with the world's best engine but no steering wheel.

This has just been my experience. I respect that it may not work for you.