Unsolvable Error 16 - Photoshop Elements 2020

I have been trying to install PSE 2020 (bought outright) on a one year old iMac that's running Mojave. I'm one user of 2 on the iMac.  I keep getting the dreaded Error 16.  I have set Permisssions exactly as the Adobe support page on this instructed, several times.  I have also tried every option I can think of:  Load with external drive uninstalled, load after Disk Utility first aid run, load via the other user.  All with the same result.  Is there another "trick" to get the program to install? I have Creative Cloud, and that often asks to be reinstalled.  Is Creative Cloud the problem?  And in the absence of success can I arrange for my purchase to be converted over to a PSE 19 version to see it that has the same installation Permissions issues? Cheers.