think you need both the graduates and the professionals for a trailer that would serve its purpose.
Studies are primarily the means to an end.
If the studies are enjoyable but the jobs you can get with the major are not, the trailer would be doing a disservice to the viewers. The first four years might be enjoyable, but the next 20, 30 won't be. That's a bad trade-off.
I understand that people currently in the jobs would have a survivor bias and would be incentivized to say good things about it due to their personal reputation and not wanting their bad words to reach the management.
But you can solve that with non-descriptive outlooks from the people in the industry. Just record how long do you work per week, how many recruiters contacted you in the last 12 months, has their salary increased in the last 12 months...
Or get their intakes anonymously.
However, via LinkedIn you can also find people who left those industries and interview them to balence the survivor bias out.