Please Presonus think outside the C:\Program Files\Common Files\VST3 box.
NO you can not add VST3 plugins to Studio One following the menu Studio One->Options->Locations->VST Plug-Ins and click "Add". You can NOT add any folder on your computer and Studio One will NOT scan it for VST3 plug-ins if they are not in C:\Program Files\Common Files\VST3.
It is not about which vst3 plug-in (although there are a lot ), it is about, being able to arrange the location of any plug-in yourself. There are plenty of reasons like HW reasons( fast expensive but small HD as C: ), weird and clumsy install and uninstall reasons, arranging reasons, anti-cluttering,
Sadly the "Ableton shortcut trick" doesn't work.
Mklink does but is a lot of hassle for such a simple feature
-- edit, why in earth would somebody vote against some useful feature like this?