What “learning” in IB will actually help your career?

I feel like every analyst rationalizes the bad hours and senior bankers rationalize their career choice by talking about how you can always be “learning” in IB. In my first few months on the desk it seems a lot of this “learning” only makes you a better banking analyst, and not a better PE associate, hedge fund investor, or any other investing/corporate role. To those that have gone on to other roles after their analyst stint, what things did you learn that were worth leaning into/ getting really good at, and what is mostly BS that we analysts can mostly go through mindlessly for our two years?