If there is another course where students design their own programming language, maybe you could use the best of the previous year's. That way LLMs are unlikely to be able to (easily) produce correct syntax. Just a thought from someone who teaches in a totally different neck of the mathematical/computational woods.
Modern LLMs can one-shot code in a totally new language, if you provide the language manual. And you have to provide the language manual, because otherwise how can the students learn the language.