Broadcast Meeting requires Basic version but machine won't release/downgrade from SFB 2016

We have an urgent need to use Skype Broadcast Meetings and during testing, we get an error indicating the "version of Skype" cannot be used with Broadcast. Research shows we need to use "Skype for Business Basic 2016" - great, no problem, right? BTW, Windows 10 version 1909 and we keep things well patched.

We have O365 Licenses and both Teams and Skype for Business 2016 was previously loaded on this computer. Also Office Professional 2013 and 2016 were previously loaded. I have uninstalled EVERYTHING related to Office, Teams and Skype on this computer. I go into the portal and select "Skype for Business Basic" and install it; however, the application that loads when we open the Broadcast link, continues to be "Skype for Business 2016" and continues to be the "not supported" version for Broadcast.

I have downloaded the "retail" free version, same result. I have downloaded from a MS article link, same result. I have tried using both the 64 bit and 32 bit versions (from both places), same result. It is like the machine is possessed! The control panel programs shows that it is "Skype for Business Basic 2016" but every time what opens is the non-functional "Skype for Business 2016" app. Despite numerous uninstalls and restarts, it refuses to leave the "Basic" version with the required functionality. I found a "lync" app profile and deleted it, same result. I found app data folders labeled "skype" and deleted those, same result.

I am at my wits end and need this functional ASAP.... Can anyone explain this? What can I do to get the supported version on this computer???

I submitted a support ticket online for help over 6 hours ago and have yet to get a response from Microsoft. I am hoping someone out there can provide a clue or have an answer sooner than that 🙂

I posted in the "answers" community and was referred here.  Thanks for your help!