Even [fill in the blank].
I don’t just mean that no one can be a world-class violist and a Nobel-winning chemist and an Olympic marathoner.
Even on a much narrower band of human achievement, you can’t do everything. There are brilliant solo pianists who are only acceptable collaborative accompanists. There are world-class conductors who would be worthless in front of a sixth grade concert band.
I have certain musical skills that are very secure and others that I am nowhere close to competent. (It gets this granular: I can read open score for TTBB, but struggle much more with open score SATB!)
I’ve found myself to be much more successful musician as I’ve gotten more secure at what I’m secure at. I’m certainly willing – eager! – to develop new skills, but when I can see my own strengths and weaknesses, I am better able to choose projects that I can succeed at.
Accept that you can’t do everything equally well – no one can do everything! When you do, success gets easier.