Mojave was a frustrating experience for me until I bit the bullet and did a clean install and remigrated my stuff. I doubt I'll do another in place upgrade again.
How do you do a clean install? Is this available from the recovery menu?
You write a bootable usb drive and format your hard-drive.
This hasn’t been necessary for many years as long as you haven’t had to replace the drive or lack an internet connection: just hold Command-R down at boot.