Hiya! 
The doc at Configure an S3 compatible object storage provider for uploads is a wiki. We are collaboratively documenting how various CDNs work. I don’t use DigitalOcean’s object storage, so I can’t provide anymore details. Perhaps you could? 
That’s a great suggestion, I like to provide a link to allow users of a service to lend their voice to prioritize fixes. I did some searching and couldn’t find a specific issue about DO’s CDN, but I found several spread all over the place. 
Which one do we link to? As a user of the service, our community relies on contributors like you to check out those details. 