This makes me want to find a side project for an excuse to give Go another try (I last used it professionally pre-generics).
I do still wish it had discriminated unions (algebraic data types) and some better error handling ergonomics.
Tagged unions can be implemented in user code, you dont actually need language support to use them.
Do it. It is just a beautiful language to write and much simpler to pickup than many others. I am a fan boy of course but I love Go.
Re unions:
https://github.com/golang/go/issues/76920
You might want to follow this proposal, if you aren't already. It's the most recent one, and it's supported by quite a few “core members” of the Go Team. I don't think it'll land in 1.28, but I like the fact that it's still a feature that's being actively discussed.