How can you disable the “iCloud Storage is Almost Full” notifications?

I’m using 4.7-something GB of the 5 GB of free iCloud storage at the moment. When I had used 75% of that 5 GB, iCloud emailed me pestering me to pay for more iCloud storage, which I do not want to do. I trashed the email and moved on. At 4.5 GB, I got a notification pestering me to pay for more iCloud storage, which I dismissed. A few minutes later, there was a notification bubble above the settings app on my home screen. I opened the settings app to see what the notification was, and it was a page pestering me to pay for more iCloud storage. I pressed “Not Now”, and it went away. Since then, the ads for additional iCloud storage have gotten exponentially more incessant. I get a notification at least once an hour, although sometimes a new one will appear only a few minutes after dismissing the old one. There is also a permanent notification bubble above my settings app, and even if I go into settings and press “Not Now” on the iCloud ad, the “iCloud Storage is Almost Full” warning stays at the top of my settings app (right below my Apple ID), and the notification bubble stays above my settings app. How do I stop this? I do not want to pay for the extra storage, which seems to be the only solution that anyone online offers. I am aware I can get ten times more storage for $12 a year, but I’m not going to spend that money when I have already paid for 128 GB of storage on the phone itself. I am completely fine if all iCloud-related services stop when this storage completely fills up, but I want the notifications to stop as well.