You could go on your old Google Apps/G Suite account and move all your inbox items and sub folders into a Old Email folder of some sort, then at least it's out of your line of sight. You can add your Outlook Exchange account AND your Google calendars on the Apple Internet Accounts section and use the Built in Calendar app instead of the one inside Outlook. You can add the Google calendar as a read-only shared calendar inside the Outlook web app which will then sync to your Outlook desktop and Mobile clients. You can export the Google calendar contents into an Outlook calendar and find a method of importing the events.
So you have a lot of options of where to go from here:
Getting back to your question though, you could potentially add the Google calendar onto your Outlook web app (visit and follow steps to add a shared calendar) - however that would only give you read access to the calendar. When you add an account on Outlook it will add everything in the account that it has access to without a way of disabling one component.
