Ah - this is something you really cannot change unless you edit the relevant XML file that details the myriad of “default” locations there seem to be these days (I can think of at least 5 supposed default VST2 plugin paths)
The best way to control what actually appears is to create your own plugin folder - copy the default plugin set (this is in the plugin manager) and then rearrange/delete & rename or create folders to your needs.