Just emailed support and they've said this is already implemented, and you can only increase your limits if you commit to 20TB of storage.
Our production web app can easily makes more than 20 requests for images per second on the initial page load for a single user. B2s new 20 requests per second cap means that it will just take one person viewing to cause anyone else also trying to view the app at that second to get an empty white screen. Cloudflare cache will only mitigate this so much.
Anyone got non Amazon suggestions to migrate to ASAP?