I have been having some issues trying to side chain fabfilter products in Cubase. The Side chain button does not appear at the top of the plugin.
I was able to get it to work by setting the side chain channel to quadro, and sending the signal to LsRs so it cannot be heard. Seems a little redundant in order to SC
Now I am really confused. Supposedly I shouldnt have to do this since Fabfilter has vst3 plugins? I thought I installed them as well…
Yep fabfilter vst3 sidechain should work in Cubase.
If there is no sidechain button you are obviously loading the vst2 version.
Go into plugin manager and check what you have installed and make sure the vst3 are in your active plugin collection.
Where should my vst3 plugins be located? When I installed them, I remember making sure vst3 was installed.
— Edit—
They are not located in my cubase vst3 folder, and I am not finding the actual vst3.dll in my Local: C/Program Files/ VSTPlugins folder. Guess I gotta go hunting… 
Do VST3 have to be located within the DAW folder and not the general VST one?
Welp, I found my .vst3 files, within Fabfilter’s respective folders. Why isnt Cubase accessing them?
I think I found the issue. Cubase, for some unknown reason, was not accessing the right files. I am completely dumbfounded as to how that happened, but it seems to be resolved now.
They MUST be in Program Files/Common Files/VST3
It’s ok if they’re in FF folders inside of that folder. Additionally if you have both 2 and 3 installed you need to make sure you select the correct one in Cubase of course.
For some reason cubase was not connecting to the right folders; after fixing that everything worked fine.