Not delegating is a very common management failure. If you’re overloaded, then get help. If your manager knows the nature and magnitude of your workload (and they should) then they will be more able to manage with you.
If you feel that stuff depends on you, then you’re probably wrong. If you’re the only person who knows how to do something, then teach someone else how to do it. It night be more work initially, but the investment will likely be worthwhile. If something needs to be done quickly, then maybe you can’t immediately delegate it, but if you ask someone to review your work, then they’ll learn from doing the review, probably, and then you’ll b able in future to give it to them as a ‘growth’ task. If you don’t know how to do something, then you’re probably not the best person to supervise someone else doing it, are you? I think that the best managers know how to do everything that their team does – but that doesn’t mean that they have to do everything.
I think that trust is important. If you trust someone to do something, then occasionally you’ll be let down, but mostly, in my experience, you won’t. Remember that trust is a positive thing – if your team trusts you to pass to them work that’s interesting and is within their capability, then they’ll be happy – and you’ll be able to concentrate on other things
If you delegate something, it’s important that you remember that although you’ve moved the responsibility for its execution, you haven’t (probably) passed on the accountability. If the task isn’t completed, then you are likely to be held accountable. So, be sure that you pass tasks on to people to can do them. If you’re not sure, then be prepared to be actively involved – be a manager.