A little update. I solved it myself with these steps.
First I uninstalled all Waves plugins. Then I uninstalled Waves central. After that I deleted everything that was left of the installation in all maps. I did a total search after everything that was named “Waves” and deleted everything of it in all maps under “user” and under “windows” and so on.
After that I did a restart of Windows and then I checked Cubase and it started normally again. After that I reinstalled Waves central and reinstalled all of the plugins, one at the time. Ant then tested to open Cubase after every new plugin that I installed.
Now everything is installed and it works. No crashes and rock solid. I had Cubase up and running for 3 hours, editing and mixing with all of my plugins.