What is the best ROI outside of my role at a REPE?

I'm an associate on a 4 person asset management team at a smallish/startup REPE ($400m AUM). My day to day is very busy, where I'm doing lease underwriting & negotiations, budgeting, coordinating with PM team on various tenant issues, writing investor performance reports, or building out our analytical toolkit.

I do good work and the hours are relaxed (roughly 45 hrs/wk). But that leaves me with a good amount of time outside of work. I wanted to know, what is the best use of my time outside of work that can help me further my career? I would ultimately like to move to a MF-type REPE or start my own syndication. (And FYI this would be the extra time that I have when I'm not working out, dating, or doing one of my hobbies, so I guess the extra 20 hours/wk.)

I guess the tl;dr of this question is: What should I be doing, part-time away from my job as an asset manager, that can further my commercial real estate or general financial career in ways that will lead me towards 1) higher compensation and 2) more challenging/interesting work?