Relentlessly pursue learning. What you learn is less important.
If I could only give one piece of career advice, this is it. Since graduation, this constant (if inconsistent) desire to continue to learn is what I'd say has distinguished me from my peers. The only reason this is not number one is because you already know you should be doing this. So instead I will try and motivate the why as opposed to explain the how, for the latter I highly recommend Barbara Oakley's course. The big secret that no one believes is that by focusing on learning, you incidentally end up achieving the more traditional goals you may be occupied with. This does not go both ways! Media conditions us to believe that if you are driven by wealth and prestige, you will self-improve your way there. But consistently the wealthiest people I have met, especially when controlling for background and age, are all intensely motivated by their own curiosity.
By focusing solely on learning, you free yourself up from the political games and posturing. The vast majority of people I've worked with are far harder workers than me both in hours and energy. I can't count the number of times I have stayed in the office a couple hours extra to do some coursework and still left before my team, working to complete some soon-to-be-forgotten slides. These are the same people who inevitably find they lack the energy or time to pursue learning, ironically opting to focus on "career". If this is you, make a hard stop. Grinding at work to earn the next promotion will always make sense in the short-term but squash your motivation for long-term development, and nobody will stop you from making that trade-off. Put in the additional hours for work insofar as it overlaps with learning something interesting, optimize for the short-term when it synergizes with the long-term.
In math terms, learning is highly non-linear and thus really difficult to keep motivated in a regular way. If you've ever been toiling on a problem for hours only to have the solution seem glaringly obvious the next moment, you've experienced this nonlinearity. Hustling at work, on the other hand, tends to feel much more linear: grind a little bit more, get a little more work done. Our brains get linearity, our brains like it. You could nonlinearly struggle your way to an elegant solution to what you're working on but that could take days or weeks, and you could just brute force it in a few hours instead. Do you optimize for the short-term or the long-term? Zooming out, this nonlinear learning function turns out to be exponential, and if you zoom out far enough, an exponential will eventually outpace any linear function.
What you are learning is less important than learning something of interest to you. People often feel guilty or stressed about not committing to learning what they "should" be learning but this is really just a more subtle extrinsic motivator. It surprises some people to learn that I read fiction and yet I probably read more novels than everything else combined. When I talk about pursuing learning, I mean simply mean actively pushing yourself out of your comfort zone. The beautiful thing about knowledge is how it builds on itself even across domains, a fact which is doubly true if you focus on first principles and intuition. Don't get so caught up in trying to learn the right things, just apply whatever it is you're learning as broadly as possible.
It is okay to not always have the energy to learn (I certainly don't) and at times there will be more important things to worry about. But if you find yourself lost about what you want to learn or worse, have no desire to learn, take a step back and start small. Try looking up the recipe for that new dish you've been meaning to cook; try skimming the introduction to that book you've been meaning to read. Or, my favorite, ask a friend who loves explaining things about something they learned recently and drill them with questions. Try to find that spark of curiosity. If you've read this far then the kindling is already there.