If you want to build something, I think that's an excellent reason to learn Python and dive in. You don't need to become a generalist before you can build something useful which you can learn from. As mentioned in the article, having concrete pain points in your coding ("Why doesn't this work?" or "how can I X?") will help you appreciate the problems that various techniques solve.

Studying other languages exposes you to issues that you might not experience on your own, but on the other hand it's hard to apply your understanding of them all quickly. Python is an excellent language to learn first.

Learn enough of one language to be dangerous, code the minimum that comes close to what you feel you need (or a toy version of it), and then you'll have a much better idea of what else you want to learn. Good luck!