If it's any help, I _think_ this is the guide I used to disable the feature: https://lifehacker.com/how-to-keep-spam-out-of-your-google-c...

It was awhile ago, but that looks like the right link and jives with my current settings. I don't get any more spam on my calendar, but obviously need to manually respond Yes to any email invites to get them to show on the calendar.