How do I delete plugins that do not properly load and are therefore not in the list of plugins?

I installed the apps "Copy Tags" and "Grammar Check" with Studio 2019. While there is a newer version of "Grammar Check" that runs with Studio 2019, there is not yet a new version of "Copy Tags". When I start Studio, I receive messages about these two older versions and the question about continuing to load the plugins. Even if I click on "Yes", the two older apps do not appear in the list of plugins under Add-ins, so I can't deactivate them there. They are also not in the list of apps that can be uninstalled.

They do not appear to be causing any stability problems with Studio, but it is nevertheless a little annoying to have these messages pop up with every start of the program.

Does anyone know how to get rid of installed plugins you don't want (for whatever reason)?