You're giving up easily IMHO, look there's always 3 sides of things for Plug-ins to work correctly : Your Computer "health" in terms of installation, updates & junk files maintenance as well as best setup for an audio rig, then your DAW and then the Plug-in itself.
Those 3 things can sometime be difficult to troubleshoot but it's not likely that the plug-in is the one responsible for the issues. In your case, you're using a brand new version of Cubase, that's also a potential issue.
If the manual uninstall/install procedure did not solved your issue, I would suggest to refer to Steinberg support threads in order to clean up Cubase plug-ins cache & database and even thinking about a complete Cubase Reset or clean installation.
I'm running hundreds of plugins with multiple DAWs on my end, and when I'm facing issues like this, I try to follow this way to proceed, step by step. Reinstalling the Plug-in first, then forcing a clean complete Plug-ins re-scan and then resetting or re-installing the DAW giving issues.
As for CCleaner, I'm running the free version since edges and never had one problem with it, IMO it really helps to clean up a lot of junk files and especially left over and unnecessary registry keys that really stack up on your PC and slow down and seriously affect Windows performances.
I'm not running Cubase myself, so I'm not able to perform any testings on my end, so I guess there's not much more I can suggest here via the direct help from the forums. Suggest that you open a support ticket with S.A then as well as reporting the issue to Steinberg support and send them your Cubase Log.
For S.A team --> @phil_johnston any insight on this one ? Some testings on Cubase Pro 11 on your end ? Not much I can do here without using Cubase. Thanks.