The quote about being a jack of all trades is *not* originally derogatory towards people who are pretty good at a lot of things.
Here it is in full:
“A jack of all trades is a master of none, but oftentimes better than a master of one.”
Robert Greene originally wrote this in reference to William Shakespeare.
So next time someone tells you to “just pick one thing” or “it’s better to S P E C I A L I Z E,” maybe you can ignore them.