I've been wrestling with this for most of my career so far. I think it's all about striking the right balance. If you're not constantly learning you will stagnate. At the same time, jumping continuously from learning one new thing to another (esp. if the things are not very inter-related) can spread yourself too thin: you need to "go deep" on some things to become an effective/valuable contributor.
I sometimes feel resentful of the amount of time I've spent as a software engineer dealing with what I often feel is boring or pure B.S. (e.g. almost everything other than designing/building some novel complex system from scratch). But in reality looking back I see that a lot of that sh*t-shoveling has actually made me much better and wiser at my profession, despite how mind-numbing and boring it often was. So I'm trying to keep that perspective to get me through those really dull days when I want to just rage-quit and move to a rural commune :)