Are you essentially asking if there's a way for cloudflare to change the host header? You can use a worker to proxy things like this, but that's going to live

Are you essentially asking if there's a way for cloudflare to change the host header? You can use a worker to proxy things like this, but that's going to live outside of the SSL settings and CF proxy, unless you set up an additional zone for "origin." and proxy apex to that.