I only have immediate knowledge of UK law, but lawyers will generally have a duty to the court to act with independence in the interests of justice. This tends to mean that in situations where one side are self-represented or using the services of ChatGPT, etc. the opposing side is under a duty not to take unfair advantage of the fact that one side is not legally trained.

They don't have to help them, but they can't act abusively by, for example, exploiting lack of procedural knowledge.

If they deliberately took advantage of one side using ChatGPT and getting it wrong because the legal foundation of knowledge isn't there for that person, that could be a breach of their duty to the court and result in professional censure or other regulatory consequences.

When did the opposing side's lawyers say anything about this? Are you confused? Law is a regulated profession. The lawyers pointing out that this is illegal aren't on the other side of the case...

Incompetent representation is grounds for a mistrial, or successful appeal.

The prosecution wants to win, but they'd prefer to only have to win once.

If you have to go back to trial, you've already showed your hand, and the defense (who is now competent) can adapt to it.

Well, it is supposed to be a Justice system, and not a game. While it is very easy to forget that, and many of the participants in it clearly don't behave as such, the outcome of it should be to be just.