Hi,
As I can see, you spread this to several threads here on the forum (1, 2, 3, 4). It’s hard to go thru all of them and make the whole picture out of them, if you leave just a piece of information at every single thread.
Please, make sure your Audio Device driver is up to date. Also make sure you have the very latest Cubase 10.5.20 installed and your plug-ins are up to date, please.