Use a tunnel on a different site

Is it possible to register a domain on Cloudflare e.g. “rainer-tunnel com” and then log into Cloudflared with that domain and then use the same tunnel on another website. For example I now have a CNAME record on another site of me to the tunnel (“tunnel-uuid cfargotunnel com”) and in the cloudflared config.yml I then have

  - hostname:
    service: http://localhost:1253
  - service: http_status:404

So would that work with the tunnel for free?

The <uuid> URL will only route traffic for the zone / domain that you authenticated cloudflared with.

Hmm okay. So could I setup multiple cloudflared instances with docker on my system and then have multiple websites or are there some limitations too??