OK, finally and after two hectic days of troubleshooting, I was able to find what the problem is. I hope this post helps others.
Dwaine, you were on the right track at your resolution. DR 16 doesn't delete its directories after the uninstall, I therefore did what you suggested above,
Next, in Windows File Explorer, delete the C:\Program Files\Blackmagic Design\DaVinci Resolve folder, if it still happens to be there. Normally it should not be there. The uninstall should remove this folder, but in some instances may not.
Next, in Windows File Explorer, delete the C:\ProgramData\Blackmagic Design\DaVinci Resolve folder.
Now Resolve should be completely removed from your system.
I deleted both folders (actually moved them to a temp directory) to no avail. But you missed the AppData folder in your resolution above. I found some DR 16 leftovers under the directory:
"C:\Users\<username>\AppData\Roaming\Blackmagic Design\DaVinci Resolve\"
I deleted that too, and voila.. everything came back.
Frustrated that I lost my projects, I tried bringing some files back little by little, was able to bring everything back, and found that the directory,
"C:\Users\<username>\AppData\Roaming\Blackmagic Design\DaVinci Resolve\Preferences\"
is what was causing my issues, not sure why! But, what's important now is that the problem is fixed and my DR 16 and my projects are back.
As simple as the fix may sound, it burned 2 days of my time and a lot of coffee
Let me know Dwaine if you are still interested in the captures.
Thanks