We already have a role, research scientist, which would fit your first description. Most of what people in the ML Engineer role would do in my company fit your

We already have a role, research scientist, which would fit your first description. Most of what people in the ML Engineer role would do in my company fit your second description. But of course not everyone in the company, let alone the industry can agree on what are the expectations of a "ML Engineer", hence the shitshow we find ourselves in.