I ran my own business, as a firearms instructor, for over 20 years. Over 500 students per year. Most of my Students were from the private Security Field, one company, armored Car/ATM replenishment and maintenance, had 400 of a staff. Police, and military.
To get the permission to obtain this status (A Instructor had to be qualified to teach, not so hard) some of the new hire in my biggest Company were ex LEO.
Most were not so special, but safe. A couple were superb shots, ex Pistol Team members, etc.
Using simple techniques to teach young Security Staff, amazing results. The majority (Canadians) had never ever handled a Revolver/Glock pistol in their lives.
Never even held one. But you can teach a person to shoot a Revolver, or a Glock 9mm, in two hours, maximum class size, 8.
Four to 6 hours, to obtain really good results, from a holster, and speed loader use, and competent reloads with a Glock 19 or 17.
This is not brain surgery.