...and I found nowhere to close them (since they don't appear, I cannot click on X).

Right clicking into widget manager didn't helped, it shows the old card widgets activated, but no option to close them...

Where is the widget user config file so I can delete those loading? Couldn't find nowhere info about this issue.

Just changed back to the old card and there the widget are, still, if that card had failed, it would be nice to have a right click remover.