WILL REINSTALLING MONTEREY MAKE IT ANY FASTER?
If your Mac has a T2 or M1 chip and is running macOS Monterey, this is simple. Back up or copy all the files you need from it, deauthorize the Mac in Music or one of the other Apple media apps, then run the new Erase All Content & Settings command, available in the System Prefs menu. When that eventually prompts you to select the country to personalize the Mac for, force it to shut down and it’ll be ready for its new user.