Generally Speaking

What shape are you? What shape do you want to be? What shape should you be? Is there a right shape? Is there a wrong shape? And what does shape even mean here? All good questions. Let's take them in reverse order.

In this case shape refers to a person's familiarity/ability in a cross-section of technologies. The generalist, jack of all trades, but master of none. The deep specialist, who knows more and more about less and less until they know everything about nothing, The focuser, not as deep as the specialist, but with a broad base. And the serial specialist, who focuses on different things at different times in their career. It's a histogram with N bins and an average/variance across the bins.

For the individual, there is no wrong shape, with the possible exception of the generalist who thinks they're an expert in everything. That's never a good idea. Outside of that, every "shape" has value. It just might not be valuable to a specific team at a specific time. An expert in SQL query optimization isn't the best person when the team is working on the mobile UI. Similarly, for an individual there is no right answer. If you're a UI developer with a focus on Android then you might be the right person for that team I mentioned.

So there's no shape that you should be. There's a place for every shape, and every shape can add value.

That leaves the last two questions, and only you can answer those. Figure out what you want. What makes you happy and fulfilled. Then figure out what shape you are, and close the gap. While you're closing the gap figure out where that shape can add the most value. It will be good for you and whatever team/group/organization you end up with. And win-win outcomes are the best for everyone.