I know this is not exactly what you said, I'm taking it to an extreme to show that relying on third party libs is not that different from relying on code your c

I know this is not exactly what you said, I'm taking it to an extreme to show that relying on third party libs is not that different from relying on code your coworkers write. Rejecting useful libraries because you "are not in control" means you're constantly reinventing the wheel, which means you're wasting time. My boss doesn't care whether I use third party libs or my own code, and I bet yours doesn't either. They care about results. You simply cannot deliver if you write every piece of your stack from scratch.