OneDrive for Business - client failing to sync

Client Configuration:

OneDrive for Business \ M365 (O365) v2108

SharePoint on-prem

Windows 10 20H2

I have a client machine with the above configuration.  We are currently using M365 v2108 but are not yet using SharePoint online or OneDrive in the cloud.  

The client machine sycn stopped working.  The client has had several technicians attempting to fix a failure to sync issue with this client.  Sync libraries removed and added several times, so within File Explorer there are several instances of OneDrive for Business Sync Libraries present although none of the instances are syncing.  At last attempt, i was unable to even remove the currently configured SharePoint library, the right-click options within File Explorer don't appear as if it is configured at all.

I would like to know how I can remove anything and everything related to OneDrive for Business, as if the client has never used it.  Then reinstall ODFB and attempt to sync the SharePoint library for the first time.

I have followed numerous posted MS docs on repairing ODFB to no avail.  I would really like to fix this rather than rebuilding a C-suite computer just to resolve the ODFB sync issue.

Any assistance would be greatly appreicated......i pray for the day when we get OneDrive fully implemented and i never have to hear the words ODFB again.

thank you