What is self-esteem? Is it certainty? Confidence? "I'm sure I'm a good friend, loving mate, caring mother, competent and motivated employee?

I have been wondering if insecurity is a somewhat bigger category than self-esteem.

I mean -- I can be insecure about whether I am loveable and loving in friendships and family relationships; whether I am competent and employable.

And self-esteem/confidence seem to be the cure.

But I also can be insecure/fearful about many other things -- climate change, death, Armegeddon, income etc.

Any insights anyone?