High Sierra freezing all the time
I'm getting the exact same thing on my iMac. Only solution is to hold the power button and do a hard reset. I've tried Onyx, resetting the SMC and system reinstall. Using Onyx doesn't help so the frustrating solution is to live with hard powering off.

I agree - Onyx and tools that try to "clear all the caches" are only a last ditch effort if you have a good backup and are willing to erase and reinstall the OS.


SMC doesn't cause freezes - it causes power transition issues like sleep / wake / blowers)
PRAM saves the volume and boot options - again, not really going to help once the system is running


Now you should do the harder fixes since they take time.


verify that a brand new user account is also freezing and hanging if you just use Chrome or the one app that freezes on your main account without all your settings and other programs.
If the freezing happens in the new account or you can't isolate the freeze, then back up one last time and erase the Mac. reinstall the OS and verify the freeze is gone. Once you're sure the freeze is gone, erase and reinstall - letting Migration Assistant bring back your apps / settings / data.


It's super rare for the freeze to come back after that, but it can happen and then you have to do the hardest of all - pin it to a specific app or a specific set of data you need to remove from the Mac.