I have got exactly the same problem with Cubase 9.5 - it quits loading right after trying to load VST 2.x Plug In Manager. Did You manage to solve the problem?
Have you tried temporarily renaming the directories where your VST 2.x plugins are stored and then re-starting Cubase to confirm whether it may be one (or more) of the 2.x plugins and its/their interaction with the plugin manager that is causing the problem?
Do you have any Waves plugins? If you do, make sure that the licenses can be read OK. I once had an issue like yours which was sorted by putting the Waves licenses on a USB stick instead of the Cloud.