> What I've come to prefer is for serialization to be implemented a the boundaries of your service, with your models at least somewhat isolated from any given serialization technique.

I think this is the right way to do it. Just like how UTF-8 to a string type is kept at the borders. Inevitably, someone comes along with a requirement that implies the first iteration of the data modeling was not only wrong, but backwards-incompatibly wrong.

It's hard to convince coworkers that it isn't code duplication though.

> Protobuf is a foot-gun here because it blends these roles in a way that's hard to get away from.

I'm not sure; in many ways it is just trying to give you a way to supply it the data to serialize with those models. I'd be nice to not have the "foot gun", but I'm not sure what such a serialization framework would look like.