Have you looked at ADK? How does it compare? Does it even fit in the same place as Dspy?
https://google.github.io/adk-docs/
Disclaimer, I use ADK, haven't really looked at Dspy (though I have prior heard of it). ADK certainly addresses all of the points you have in the post.
I personally haven't looked super closely at ADK. But I would love if someone more knowledgeable could do a sort of comparison. I imagine there are a lot of similar/shared ideas!