I believe learning languages is generally a net good. But to answer your question, it would help to know: why do you want to learn Russian?

If you just find the idea of the language interesting, then yes! Start leaning it. If you have motivation, that will help.

Is there specific media you’re looking to consume in its original language, Russian? Then yes, absolutely :).

Are you just trying to learn “any Slavic language”, to extend the language families you have knowledge of? You already have some Polish, so what is it about Russian that attracts you? Is there another language that might have more resonance or utility for you?

As far as I am aware, mostly sue to Soviet influence, Russian is probably the most-widely-understood Slavic language, so this does offer some advantages. I have spoken with Ukranians and Georgians who now don’t like speaking Russian, for obvious reasons, though I don’t know how widespread this feeling really is. And at least here in Germany, I feel like Croatian, Czech, or Slovakian would be a more useful day-to-day or holiday language, but itball depends on your goals.

And, as a dentist once told me in regards to dental floss, but it applies here too: The best language to learn is the one that you will actually learn. If there’s a language you’ll actually stick with, that’s good.