Just my two cents: Apple Home can handle well over 500 devices, and power users have even documented setups with around 1,000 devices. To reach that scale reliably, using Matter over Thread is essential.
I’m currently running roughly 100 devices paired with Apple Home, and they have been extremely reliable. My Homey is on order, and once it arrives, I plan to share these devices with Homey using Matter’s multi-admin capability.
In this setup, Apple Home will handle the network side (with multiple Apple border routers forming a single Thread fabric), while Homey will be responsible for the more advanced automation logic. Once my Homey arrives and I’ve had time to properly test this approach, I’ll be happy to share more concrete results.
Edit:
My setup and strategy is here: Back for another try
