CLOUDFLARE SERVICES FOR PRIVATE ORIGINS IS NOW GENERALLY AVAILABLE

Summary from the TLDR Founders newsletter

Cloudflare services for private origins connects internal services to the Internet without exposing a public IP, opening a firewall port, or running cloudflared alongside the origin. It gives private applications the same protections and controls used for public applications. Argo Smart Routing and Dedicated CDN Egress IPs aren't supported, and origin health checks require Load Balancing.