Error: PKG can't be opened because Apple cannot check it for malicious software. How to open a Primera app that hasn’t been notarized or is from an unidentified developer?
Primera is in the process of getting all of its drivers and application notarized by Apple.
Here is how to run the application anyway after you get the error that the application is not notarized or from a trusted developer:
In macOS Catalina, Mojave or Big Sur, when an app fails to
install because it hasn’t been notarized or is from an unidentified developer,
it will appear in System Preferences > Security & Privacy, under the
General tab. Click "Open Anyway" to confirm your intent to open or install the
app.
The warning prompt reappears, and you can click Open.

The app is now saved as an exception to your security
settings, and you can open it in the future by double-clicking it, just as you
can any authorized app.
Article ID: 101819