...as I get stares (okay, mostly of fear) if I point out that we need a branch in my workplace. What you can/can't do (sanely) with your tool shapes how you think about its problem space.

To emphasize that even more: Try to explain the concept of an ML-style sum type (i.e. a discriminated union in F#) to someone who only knows languages with C++-based type systems. You'll have a hard time to even explain why this is a good idea, because they will try to map it to the features they know (i.e. enums and/or inheritance hierarchies), and fail to get the upsides.

Easy, is is called std::variant, available since C++17.

Yeah, I guess. Except that std::variant is basically a glorified C union with all the drawbacks that entails.