I think you might not quite understand the point of Meshtastic.
Blockquote An open source, off-grid, decentralized, mesh network built to run on affordable, low-power devices
The primary purpose is off-grid mesh networking communication. So, really the network is what you build.
However, there are some options that are available that will help with what you’re trying to achieve. For example a Matrix relay. M <> M Relay See their GitHub: GitHub - geoffwhittington/meshtastic-matrix-relay: A relay between a Matrix.org room and a Meshtastic radio. This relay extends your Matrix.org-based communication with a LoRa-based Meshtastic radio mesh. This is not an official product of Matrix.org or Meshtastic.
I’m not sure what you mean by this. In reality you only need one node setup as MQTT on your network and from there you have a connection to whatever you have on the other side.
Lastly, remember that this is an all volunteer open source project. We’re very fortunate that we have pretty active and engaged developers but they are not capable of meeting every request that people have.