> I've seen the curve and the pain it's caused, and would never use it for any code that needs to be performant or actively developed on the multi-month or year timescale

Typed python is safer and more maintainable than Go. Slow as a dog, but it's really a hard choice when choosing performance and a bad type system with a half baked language vs a good language with a good type system that is a bit of a drag on performance.

And you really don't have to go all in typing. I have worked on gradually typing code bases and it pays off from day one almost.