How about instead of a save we use a skill check? What do people say?
Casting Time:1 action
Components:V, S, M (a book)
Duration: Concentration, up to 1 minute
You impart your knowledge to three creatures with an Intelligence score of 5 or higher and possibly overwhelm the target. Choose nature, religion, arcana, or history, and make an Intelligence check for that skill. Each target must make the check as well. If their check is lower then your check, they are stunned.
At the start of each of its turns, the target can make another skill check with the DC equal to your check to end the effect. On a success, the spell ends. Damaging the target instantly ends the effect.
When the effect ends, the next check the target makes using that skill is made with advantage.
At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the number off affected targets increases by one for each slot level above 2nd.