Hmm. Can’t seem to get Home app to recognize ANY of my smart devices. I’ve got LIFX smart bulbs, Meross switches and outlets, a Sensi thermostat, and Harmony remotes. Only detected devices are my two AppleTVs. 
None of the LIFX, Meross, or Sensi devices require hubs; they just connect to wifi. The two harmonys have their own hubs that also just connect to wifi.
I’ve got several devices from Meross that work great with homekit, in fact I didn’t even use the Meross app to set things up. I did it all through the home app.
I moved this to a new thread so we could hammer things out if need be. 
Make sure your Meross devices are the Homekit versions. They have both available with and without Homekit compatibility.
The Threads/Matter standard is very close but not in operation yet that would allow all devices manufactured by companies adopting the new standards.
Also, it takes a second gen ATV4K to support Threads.
https://discussions.apple.com/thread/253929730
Here’s a good run down on Matter.
Tbh HomeKit kind of sucks for device availability. Unsupported device can be added to HomeKit by using homebridge running on a server (I use a RaspberryPi). I’ve been able to add my Sony receiver, my lgtvs, my two harmony remotes and all of my Zigbee/z wave devices in Smartthings.
Provided someone has written a homebridge plugin then the device will show up in the home app.
As for matter and thread support that needs to be added by the device manufacturer. If it’s an older unsupported device (like the harmony remotes) then you’ll probably be stuck using homebridge.
Ah. My Meross switches (a bunch of single pole switches and a few three-way ones) and smart outlets are all the non-HomeKit versions. My LIFX bulbs similarly cannot be enabled.
From LIFX: " All current LIFX products have a hardware chip required for Apple Home functionality. Products not compatible with HomeKit include the LIFX Original, LIFX, 650 Color, Color 1000, White 800, LIFX Z generation one."
Why the heck do devices need a proprietary HomeKit chip?
Both LIFX and Meross have iOS apps, and I can control my devices with 1-touch widgets on my iPhone. Why can’t Apple allow those apps to access Siri? They are just sitting there on the Wifi, and clearly my phone connects to them without issue. Fracking Apple… 
See here:
Thank you. I started looking into this. I run a Synology, but it looks like I might need to update to DSM 7 for best results, and I’m not really ready to risk that at this time because I currently have only 30gb free on a 40TB server 
.
But this does seem to be the best way to go about making everything work with HomeKit. (So weird. It only proves Apple could do it themselves if they wanted to.)
Thanks again — really appreciate the info.
It runs well in a docker container on synology How to Install Homebridge on Your Synology NAS – Marius Hosting
The first homekit products did. It was to secure connections with 256bit hardware encryption. Eventually, though, apple decided that wasn’t necessary and now also supports software encryption.
Yep I have long been a convert to Meross stuff.
Smart Lamp, Main lights and Strip lights behind the TV.
And that’s just the main bedroom.
I had the same issues only to find I need to have an iPhone, watch or some sensor to enable proximity sensitive devices to enable HomeKit programming…