Speaking as a such a boss, the idea of doing ‘bad things’ to somebody in the name of team retention seems rather counterproductive!
If somebody’s made up their mind to leave, the best you can do is ensure it’s as amicable as possible, then a thorough exit interview to understand where you went wrong and try to fix those issues to course correct & retain others.
That is the best mature, professional people can do.
Spiteful incompetents, on the other hand, don't think that there are issues they should fix (the employee isn't a good fit); are afraid of exit interviews; and can be unprofessional enough to burn bridges and damage the company in order to damage the quitting employee.
If somebody’s made up their mind to leave, the best you can do is ensure it’s as amicable as possible, then a thorough exit interview to understand where you went wrong and try to fix those issues to course correct & retain others.