Discourseで複数のサイトを管理するためにNginx Proxy Managerを使用する

Sure, why not?

Just make sure, you‘ll have to expose the right port and set up this port for your domain in Cloudflare tunnels.

Personally, I don’t prefer this solution because it makes me dependent to Cloudflare and every tunnel agent puts a hole :hole: into my firewall, that makes me feel I‘m installing a trojan horse.

Firewall management is essential for server admins. You‘ll have some homework to do before exposing sites to the DMZ.