John,
I was able to get Fusion 360 working again after a second exercise of manually uninstalling Fusion 360 as you had previously suggested. I noticed after reading your directions again that I did not restart my computer after installing Fusion 360 for the first manual uninstall. I did this after the second manual uninstall I performed.
I also did not disable my AV on the second install. I let my AV manage giving Fusion 360 permission to get through its firewall as this is what I did in previous Fusion 360 installs. I also found out that my Windows firewall was also enabled. It must have been enabled during my recent update to Windows 10 2004. I have permanently disabled the Windows firewall and only have my Bitdefender firewall running.
I think it was a combination of the restart after Fusion 360 install and allowing my AV to manage firewall access which made the difference.
All in all, I would still be dealing with this issue without your help.
Many Thanks!
Roosevelt