We're really sorry for all the trouble. Which version of Photoshop Elements are you trying to install? Also, only Photoshop Elements 2020 version is compatible to use on Mac OS Catalina.
If you facing issues installing Photoshop Elements 2020 then, please enable the hidden admin account in Mac and try installing the application there. Refer the following link for the steps: https://support.apple.com/en-us/HT204012
In my first post you can see that I am on Catalina.
In the meantime, however, I was finally able to install the app after deleting everything adobe related on my Mac. This was done by going through all folders on my Mac and deleting all references to Adobe. I don't know which file or app (current was only flash and acrobat dc, rest were uninstalled ages ago) was the offending one but it worked.
I have had various adobe applications on my machine over the years, some bought some on a trial basis, all left behind a trace here and there.
So the problem lay with either the current adobe apps I had or with residue from past apps. This may be something to look into.
There is no need for further follow-up at this time.