iPhone 13 Google Calendar notifs don't work unless CREATED on iPhone

I have the exact same issue as this forum here.

It seems like bad forum etiquette that CKR83 suggests they found a solution and then doesn't say what.

But the forum is now locked and I can't contact them.

Regardless, my notifications just do not work despite toggling and checking all the settings. They only work if I make the event/reminder/etc. on the iPhone. Even if I edit the notification after making it on another device it doesn't work. They show up in the calendar so it's very deceptive, and I assume that means it's not a syncing issue. I have even tried uninstalling/reinstalling the app and still no luck.

I just need answers. I thought I could trust my calendar since some of the reminders work and they appear in the calendar. I thought I was going crazy until I tested things. Plus I missed or nearly missed some important events. Please help!