I want to know if there is a Google Calendar app for the Mac desktop? I do not want to sync my Google Calendar to my Apple calendar. I want to have the Google Calendar app itself on my Mac. Has Google made this?
Google haven’t made a desktop calendar app. You can add your Google account to Internet Accounts in macOS which will allow you to access your Google calendar in Calendar.app without syncing it with your iCloud account. Alternatively you can use Fantastical which also supports Google Calendar.
Just use the WebCatalog macOS app. Create a new Google Calendar app, sign in as you normally would, and then in the Preferences select 'Remember last page visited' so you don't have to sign in again. I run a number of Google and other services like this as one-off apps.