Screen mirroring remote proctoring

I want to know how I can see the screens(entire desktop and all actions) of four users simultaneously. I don’t want to take remote access . I want to just see all the activities of 4 users for 3 hours. It is for the purpose of remote proctoring. I don’t want to whitelist some applications because they can use the browser to open files but not for using the Internet. They can use a pdf readers but not for seeing previous saved files.v

Current remote proctoring systems I know about doesn’t let you switch tabs or move away from the tool. This won’t serve th purpose because they have to be tested on the ability to use office applications. It has to be Easy to use for teens (15 year olds) And to be able to see all 4 screens at my end but they should not be able to see any screen except their own. It should work on windows PC/mac.

What tools are possible to use What is the cost Are their any freeware..I just need it for 3 hours each day for 2 days.