Slightly off topic, but the sheer size of the ToC of the Mixing Swift and C++ page[1] makes me think I'm better off just learning and using C++.
Any language that makes programming easier is good. Modern C++ is also quite good, but I feel like there are more "nice to haves" in other languages. Reflection is one, for serializing things without boilerplate and his uncle. And just reflecting on types in general can be nice.