ESPHome for wired interconnection (e.g. via PJON)

**Describe the problem you have/What new integration you would like**

I like to start a discussion on **wired interconnection** of ESPHome sensors.

**Please describe your use case for this integration and alternatives you've tried:**

ESPHome is lacking support for wired-interconnected devices. I used MySensors in the past, but the ESPHome approach with integrated OTA and security features is much more powerful.

See illustrations below for current / wished architectures.

**Additional context**

Hello fellow ESPHome'ians and HomeAssistant'ians,

I like to start a discussion on wired interconnection of ESPHome sensors.

Some time ago, there were some issues (https://github.com/esphome/feature-requests/issues/1655 and https://github.com/esphome/feature-requests/issues/1288) related to this, but there was not much activity and no follow-ups.

I drew a sketch, abstracting my current home automation:


For several reasons, I like to migrate to ESPHome. This is my dream setup:


I am working as a researcher in hardware design (especially FPGAs). So I know hardware and software stuff ;)
For several weeks I started to dig into the ESPHome sources, but still, I could not figure out what has to be done to make ESPHome more "wired"

**Central question: Can the underlying ESPHome interconnection system be re-routed to not using TCP but first passed to a Gateway and then routed via TCP to Home Assistant?**

If it is possible. Could you point me to some code, so I could work on some more detailed architecture?

Actually, I don't care much about the underlying protocol (e.g., CAN, RS485, PJON(https://github.com/gioblu/PJON) ) as long as it is capable of driving ~30 physical sensor nodes with ~500m wire (Build a house and have several YSTY-0.8 with at least 4 wires basically in every room ;) ). Throughput is not critical. Let's assume < 1kbit/s sensor.

Happy to provide you with more details and looking forward to some discussion!

~ Martin

Draw.io image source here: https://github.com/esphome/feature-requests/assets/29856783/2a9aad30-a897-4fc9-86ed-82eb350e6b96

The issue does not name a file, test, or entry point; it asks for an architecture for routing ESPHome sensor traffic through a wired gateway instead of TCP. Start by mapping the existing ESPHome interconnection sources and compare CAN, RS485, and PJON against the stated scale, wiring, and throughput requirements. Done would be an agreed design with a concrete implementation scope.

Written by the indexing model from the issue text.