Jellyfin apps wont connect to server using URL inside my network

I installed Jellyfin yesterday because of all the Plex drama and really enjoy it.

I have split DNS configured, i.e the URL resolved the internal IP when inside my network and public IP when outside.

From my web browser, I can reach the JF url, login and play videos no problem. However, the iOS and Apple TV apps wont connect using the URL when on my wifi, using the IP address works fine. This is an issue because I want t set it up for the wife and kids on their phones/tablets and trying to get them to switch servers when not on the home WiFi is not an easy task.

What am I missing here to have the URL work internally?

Edit(Additional Info): I do have the option enabled "Use same published server URI for internal and external access" with the URL filled in.