The steps to fully uninstall Dynamo (any version pre 2.1) with installer is mentioned in an old blog post (all the way to the end): https://dynamobim.org/working-with-dynamo-in-revit-2016-and-revit-2019-simultaneously/. Sorry for the inconvenience our team introduced to you. What you have seen is caused by registry not fully removed by the default uninstaller.
Hi
I have the same problem. I installed Dynamo version 2.0.3 but when I uninstalled it and tried to install version 2.0.2 it says I cannot install it since a newer version of Dynamo has been already installed. Could u please explain me how to uninstall it from other users?