Cubase 10 recognizes the native instrument as vst2 and puts it on the blacklist

[P.A.T]

You can try the following:
Quit Cubase
Search in the user settings folder
(e.g. “C: \ Users \ … \ AppData \ Roaming \ Steinberg \ Cubase 10_64”)
the file
Vst2xPlugin Blacklist Cubase.xml
Delete this file.
(It will be regenerated the next time Cubase is started)

If you want to look more closely at the problem:
Open the blacklist file with a text editor

Find the sections that belong to your plugins, mark these areas, starting with < item > up to < / item > and delete them, then save the file.

Here is just an example of what that might look like:

regards, Pat