Hehe, yes and no. The reality is that I hardly ever have to do it these days, even though I look after a few machines, so I’m often scratching my head trying to remember what I did last time. The “how” depends a bit on whose machine it is and what I suspect the problems might be. From memory…
By far the simplest way is to make a Time Machine backup before starting and use the Recovery partition that all modern machines have, or network install if that isn’t available, to erase the boot disk and reinstall the OS. Then you can just restore from the TM backup, using Migration Assistant, when you’re setting up the fresh install. This tends to fix things that haven’t been cause by a user doing or downloading something dodgy.
If the problem is in the user’s account though, which you can sometimes determine by creating another account and testing for the problem there, you may need to do something a bit more granular and time consuming - reinstalling apps by hand after the OS reinstall and adding back user data either from a backup or by just logging in to the appropriate cloud accounts. This is what I think would be a good idea for @Arky’s Monterey issues.
Last time I got a new Mac I wasn’t near my home machine and hadn’t fully decided how I wanted to integrate the new one, so I just logged in with my AppleID, installed Dropbox and logged into my account. Within a couple of hours I had most of what I need to work and play. After downloading a few apps I was almost all the way there. I do this kind of nuke and pave with any of the work machines I’m responsible for. Works well for them and is pretty fast in terms of the time I have to spend on it. Especially with an external drive to boot from.
I also use Carbon Copy Cloner to make a full backup of any machine I’m working on before I start messing with it. I’m not associated with them, though I am a very happy paying customer. The software works really well and the company is excellent to deal with. Other people swear by SuperDuper!, which is also good and does a similar job.
Something I’ve always used in the past, but isn’t as important these days, is a dedicated external drive that can boot the machine I’m working on, and that has a copy of the OS I’m reinstalling. I used to always use them in the days of slow/limited internet, but any Mac with a security chip - T1/T2 etc - needs to have a setting changed before you can boot from an external drive, so you have to test before going down this route. I wrote about the steps to change security settings here.
I currently have a fast USB thumb drive with 3 partitions on it for use with the different OS versions I have to deal with. I hardly ever use it.
