'incentives' won't help. there simply isn't enough supply in aggregate. and they are not leaving because of a lack of pay they're leaving due to the stress of dealing with assholes on the daily. cash isn't going to fix that problem.
the only option left in such a scenario is literally mandating they return to work. which doesn't nothing be return you to initial workforce levels it doesn't increase capacity.
we're seeing this right now with the national guard 'mobilization' in some areas. they're literally doing nothing but sitting with patients and other menial tasks that don't require training. they're basically just in the way.