The solution, which you say you don’t want to do is create a new or modify an existing Collection. You can create whatever structure makes sense to you, including having the same plug-in appear in multiple locations. I suspect that the item named “category” in Sonar is not the same as what Cubase names “category” (which is the developer’s description) and more like the names given to folders in a Collection structure.
If you don’t want to use the tool that is designed to address your issue…? ¯_(ツ)_/¯