You can break down a big feature into smaller bits of code, but what's the point of releasing a some new code that's not being called by anything yet, when you might change it as you converge on the final solution?
What's the point of a PR that's just an HTTP handler + adapter that's not exposed via an endpoint yet, and might change once we implement related the domain layer methods? What kind of context will a reviewer have on whether this is a decent handler + adapter when there is no other context about which methods the handler will call and what data will be returned?
If we release the domain layer first, we may want to adjust the domain data model in order to better serve the application layer, or work better with the infrastructure/datastore layer.
And so on.
IMO the PRs need to be big enough to encompass an atomic, complete unit of functionality or else it's basically impossible to tell if the approach and code is any good.
"It doesn't break anything" is not good enough, you can still create tech debt by releasing code that may need to be changed to complete the feature. Or someone will just implement the rest of the feature in a worse way in order to integrate with the non-ideal code that you already released when you didn't have a good enough view of the final solution