Reinstallling macos

The only thing I see that pertains to my iMac that I haven't tried was this:

• Disconnect external devices other than your Apple keyboard, mouse, and display. If that resolves the issue, gradually reconnect your devices, testing each time, until you find the device that is interfering with sleep. Then check the documentation that came with the device, or contact the device manufacturer.

I'll look into that the next time it happens. It doesn't happen every time. But maybe once every day or so.

So the machine went 3 days without locking up or failing to fully wake from sleep after the reinstall of MacOS. So I decided to reattached one of my external hard drives that morning. Came home that afternoon and had the freeze up happen again. I managed to SSH into the iMac and do a graceful reboot and detached the drive. Haven't had an issue since. The drive is 4 years old so I'm thinking it might be the beginning of a failure. Plus, it's USB 2 and my 2017 iMac 27" has USB 3 so it feels like a good opportunity to update anyway.

That said, has anyone else here had external drives cause wake from sleep problems before?

All this said, if I do reinstall using the Recovery partition, I know it says I'll keep all my files. Does it also keep all my users and all the third-party apps I've installed?

I just made clone with Carbon Copy Cloner and went for it. The reinstallation worked without a hitch. I'll see if this solves my wake up issues.