Train ticket for student internship?

So, I have a three-week student internship starting in March 2022. Since I'm thinking about doing it at the airport, for example (when it's possible again), I need a train ticket. A regular student monthly ticket costs just under €300. Does anyone know of a cheaper alternative? For example, this NRW Azubi Ticket. And does anyone know how much it costs? And, of course, whether it can be used for a student internship?

P.S. I live in North Rhine-Westphalia, and the airport (Düsseldorf) is 85 km away.