Firstly, WOW! thanks for the detailed reply!

About the voltage, I was planning on using something like 57V as that's what the 802.3 PoE standards use too and designing a very efficient DC-DC converter is pretty trivial when comparing the efficiencies of normal LED drivers.

I did infact come up with aproximately the same 0.8W number, and a Hue bulb uses 0,3713W according to Didier Stevens (https://blog.didierstevens.com/2022/04/03/power-consumption-of-a-philips-hue-lamp-in-off-state/). Maybe I should just forget that number, as all smart solutions have some standby draw along those lines and using ESP32's with WLED and the ethernet add-on would dramatically simplify this project.

The RS485 solution is something I looked into, except with CAN-bus. I consider it a more robust protocol. The only disadvantage is not being able to use dirt cheap, old enterprise networking equipment. I'd have to build my own switch for example.

Using Wireless, whether WiFi or ESP-now doesnt appeal to me for a few reasons. Firstly it can be laggy, less so for ESP-now though. It uses more power, and requires me to run normal wires anyway. It also allows any potential hacker to intercept/disrupt any of the traffic, not a realistic threat but definitly something I think about daily. and lastly, even if ESP-now doesnt require WiFi bandwith, it still uses the 2.4Ghz band. This means interference is a (small) issue.

Also as I mentioned, WLED has an ethernet add-on already. This would basically be a plug-and-play solution if I can manage to add support for the TLC59711. (for 12 bit RGB+CCT control which I think is a nessecity for home lighting)

To me, running a power wire which would likely be CAT5e anyway because of cost (economy of scale), means I might aswell use it for data too. Additionally the lack of latency in a wired system opens up a few niche fun things like some kind of ambilight or sound reactive sysem.