ok there's theory, then there's practice. "prosecutors are concerned about ethics" in my experience in practice they want convictions, to the point of advancing absurd arguments, and yes i can give specifics. they may not all be like that, but that's the job description--get convictions.
No, the job description is not to get convictions. I've worked as a prosecutor in 3 different jurisdictions, and in none of them was the job description (either explicitly or implicitly) to get convictions. I know how many jury trials I've done, but couldn't tell you what my "record" is. We went forward on cases when we felt we had enough admissible evidence to convict, which is not the same as when we "believed" the person was guilty. We also dismissed cases when we knew the person was guilty, but discovered that the stop or search was improper and the evidence was going to get suppressed. I realize not all prosecutors operate this way, but I believe it is the norm rather than the exception as you appear to believe.