Settings -> System -> Multiple users.
Add another user, and install all your spyware apps from this user account. These apps should be unable to access your primary account, including other installed apps, they will see only an empty Android phone.
You will need to create a new Google account on your PC first if you want to install apps. Also configure two-factor authentication using your PC or another phone, because you won't be able to switch to your authenticator app on your primary account quickly enough to copy the one-time password to your new account.