Damn you, imposter syndrome!

I tend to feel that I have so many irons in the fire, I will never master any of them, so it is hard to get to the level of achieving "imposter" status...

and my goal is never to become "the best" at anything really...but just to become good enough to not be a detriment to whatever I commit to doing
The only thing to do is to keep attacking the problem, which is playing and learning how to play, and try to gain some perspective in the long term. More playing and more interacting with more musicians help that.

And understanding that people have different strengths. What someone else does may be impossible for you, what you do may be impossible for them. And understanding that there will always be others more accomplished than you, and you don't need to interpret that as meaning they're for real and you're not.

And stop BSing yourself. Ambitious musicians get into this self-inflating, self-promoting thing-- if you're living in a fantasy world you created presenting yourself as a cat, you're going to get zapped by it when a real cat comes along. Either suppress all shame about that, or learn to not kid yourself about it.