A good lawyer can also be a scumbag. Plenty have made giant piles of money doing things that most everyone would think was immoral. They were good at what they did but bad at the whole being a decent person thing.There are definitely scumbag lawyers but, in my experience, those people tend not to be particularly good advocates. The best way to lose credibility is to be caught in a lie. Bad lawyers blindly assume that everything a client says is the truth and never admit there are two sides to a story.
The best lawyers are able to take provable facts and tell a convincing narrative that meets the client's objectives. Sometimes it is a ***** of a job.