An unruly passenger should be charged for the fuel used to land and takeoff. The maintenance fee for one hour of flight and any incurred loss the airline has due to this. However, I would prefer zip ties and duck tape, fly to destination and have he or her arrested and charged.
Charges get dropped. The airline needs to take the wheel - yes, charges for fuel and any lost flight time, reimbursement for hotels for travelers if they are affected.
And those loudmouth violent passengers need to be banned permanently.
This gives a rough idea. Somewhere around $150,000
https://thepointsguy.com/guide/how-much-cost-plane-diverts/