The real problem is going to be where history matters and you can't delete - for example archive.org and httparchive.org. There is no way to reproduce the content in the archive obviously, so no one will be deleting it. The only way is to start a massive (and I mean MASSIVE) sanitization project...
At this moment problem is not in Cloudflare's side, search engines crawled tons of data with leaked information, even though Cloudflare drops their caches, data is already in 3rd party servers (search engines, crawlers, agencies)
That might work. If said 3rd parties were interested in helping. Most of them might be but it just takes one party refusing to help and then you've still got the data out there.