Not sure know how far you may be into your career but as one who’s had a couple decades, it’s definitely possible to have both. I have been able to learn two very different languages (C and Haskell) to that level of comfort and am feeling nearly there in Rust. At the same time, I feel reasonably comfortable picking up a project in any of about 20 others with frequent reference to standard lib docs.

With only my own experience and that of people I’ve worked with to go by I can’t provide any broader scope, but I feel like it really is the case that a critical mass of familiarity with different languages and ecosystems makes it far easier to pick up and run with others and be more or less unaffected by the differences. It is probably important that the languages in your set be actually different though, rather than superficially different as most historically-popular languages have tended to be.