He doesn’t really have a legal strategy. It seems more accurate to say that he has an illegal strategy, in the sense that he is “defending” himself by delegitimizing the court, and the rule of law in general.
The basic assumption of the law is that everybody recognizes its authority. Defendants may lie, seek to intimidate, or corrupt, etc etc, but they’re still seeking the right legal outcome. Trump’s approach is “fuck the law, when it seeks to make me recognize its authority it is by definition illegitimate.” Not a lawyer, but I don’t think there’s any law against treating the law with absolute contempt. I think Judge Merchan is trying really hard, god bless him, but I’m not sure he’ll be up to it.