Server with multiple applications, how do I use DNS/Hostname correctly


I’d like to install Jitsi Meet on a hosted vm, where I already have applications running like Teamspeak or Nextcloud with domains like

Now I would have created another subdomain for Jitsi with Can you explain to me why I have to set this as the hostname and what would be the best practice if I want to keep my old hostname?

I don’t quite get why Jitsi Meet relies on the hostname, I never encountered something like this before.