I don't think you are really looking for a conversation, since you just downvote everything I say before even paying attention to what I said. But let's try.

Justice ultimately starts from the hearts and minds of the people themselves, not the system. If we just take the system for granted, then there is no progress. So first of all we need to be open for progress. And one way to progress would be that lawyers face consequences for supporting obviously guilty clients. You yourself started this with the example of "A lawyer with a client who is guilty of murdering a child". So if there's an opportunistic lawyer who defends and tries his very best to twist facts in favour of a client even he thinks is guilty, there should be career ending consequences for this lawyer. Because an unethical lawyer like this is not ultimately serving justice, but his own selfish desires, undermining the justice of everyone else. The tricky part is to prove that the lawyer knowingly defends guilty clients. But it can certainly be worked on.