Interesting. In this example where the parent comment discusses using a proxy from AWS to Linode/Hetzner to Cloudflare, then I'd go with someone in the Bandwidth Alliance, which would include Linode and Vultr.
Have either of those actually implemented Bandwidth Alliance? Last I looked(few months ago), the only outfit that had actually done anything on that was Backblaze. Vultr and Linode were nothing more than announcements with no actual cost savings for customers implemented.