Hi, I'm building a single-storey house with an attic (160-170 m² and a Faraday cage in the form of underfloor heating) and I want to do a fully DIY automation. I would appreciate an evaluation of my idea and all the heebie-jeebies on its silliness, as I am totally green on the subject
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Assumptions:
Automation definitely not over WIFI. I'm thinking zigbee/matter/partially wired
12 V DC circuits: I will run 2-3 separate 12 V lines to each switch/socket for sensors and ESP32 modules.
About 100 ESP32 modules: At each ESP32 point with Zigbee/Matter. Applications: dimmers, temp/humidity sensors, flood detection, current measurement, security system (noise opening sensors).
Redundancy for security: Critical ESP32s (security sensors) will have PoE (Cat 6A) 12 V DC emergency power bank.
Home Assistant server: On a virtual machine (Proxmox) in a rack. Hardware: 16 GB RAM 4 CPU cores. Is this enough for around 100 devices?
Questions:
Zigbee vs Matter: I'm leaning towards Zigbee (mature), but Matter offers versatility. Is it possible to make DIY sensors on ESP32 with Matter? Because with Zigbee I've seen such wonders Link
Zigbee coordinator: one Sonoff ZBDongle-P (Zigbee 3.0) in a rack - will it handle 100 devices on two floors?
ESP32 programming: ESPHome doesn't support Zigbee, so I'll be patching code probably from scratch. Anything worth considering here?
Server: Is 16 GB of RAM not excessive for a HA Node-RED Zigbee2MQTT?
Next steps:
I will buy 2x ESP32-C6 for prototyping (learning Zigbee/HA) sensors. Anything worth considering? Will the Sonoff ZBDongle-P be of any use to me right now? HA I want to host on VB on the comp for now.
Thanks for all the comments!

Assumptions:
Automation definitely not over WIFI. I'm thinking zigbee/matter/partially wired
12 V DC circuits: I will run 2-3 separate 12 V lines to each switch/socket for sensors and ESP32 modules.
About 100 ESP32 modules: At each ESP32 point with Zigbee/Matter. Applications: dimmers, temp/humidity sensors, flood detection, current measurement, security system (noise opening sensors).
Redundancy for security: Critical ESP32s (security sensors) will have PoE (Cat 6A) 12 V DC emergency power bank.
Home Assistant server: On a virtual machine (Proxmox) in a rack. Hardware: 16 GB RAM 4 CPU cores. Is this enough for around 100 devices?
Questions:
Zigbee vs Matter: I'm leaning towards Zigbee (mature), but Matter offers versatility. Is it possible to make DIY sensors on ESP32 with Matter? Because with Zigbee I've seen such wonders Link
Zigbee coordinator: one Sonoff ZBDongle-P (Zigbee 3.0) in a rack - will it handle 100 devices on two floors?
ESP32 programming: ESPHome doesn't support Zigbee, so I'll be patching code probably from scratch. Anything worth considering here?
Server: Is 16 GB of RAM not excessive for a HA Node-RED Zigbee2MQTT?
Next steps:
I will buy 2x ESP32-C6 for prototyping (learning Zigbee/HA) sensors. Anything worth considering? Will the Sonoff ZBDongle-P be of any use to me right now? HA I want to host on VB on the comp for now.
Thanks for all the comments!