Unfortunately, this is one of the major & significant flaws in Airtable.
This is not possible unless you change your primary field to become a formula field which incorporates the other fields that you want to display. And, of course, doing that might throw off all the other parts of your system which have already been finely tuned & perfectly calibrated.
Sadly, people have been requesting Airtable to fix their calendar in this way for years, but nothing yet. You might want to try your luck by throwing your hat into the ring, too. Please send an email to firstname.lastname@example.org and let them know how important it is for you to display another field on your calendar besides the primary field.
However, the great news is that @Kamille_Parks has solved this problem for all of us! :grinning_face_with_big_eyes: Kamille has added this as a feature in her excellent Master Calendar app, so the solution is available to us today! :cowboy_hat_face: :horse_racing: :raised_hands: