If you could allow for a quick follow-up question.
When you reset the VUM database did it also wipe out any ISO \ Vender (Dell/HP) imported ISOs?
Nimble Connection Manager, ISM-Dell...etc
https://kb.vmware.com/s/article/2147284
The above KB offers this warning so I have to assume it is "fully" destructive - just looking for confirmation.
Cautions: The following is a destructive task. Ensure you have working backups and/or snapshots of the vCenter Server Appliance 6.5 / vCenter Server Appliance 6.7 and make a note of all custom configurations like proxy settings, third party download URLs,customized baselines, etc. before proceeding.
BTW - I am on 7.03Ua