We have a web server behind firepower in the DMZ, and we've implemented an SSL policy for decrypting traffic with a known key.
In our domain name (forexample.com), we've directed traffic to Cloudflare Proxy. Within Cloudflare, the traffic is then forwarded to the public IP of the web server. Additionally, on our firepower, we've configured access to the web server to only allow traffic from Cloudflare's IP ranges to Webserver on HTTP and HTTPS, and it work fine, users can access on both protocol.
the only issue is , on firepower we are unable to see any HTTPS traffic from Cloudflare ranges to Webserver.