This was a very interesting read. I’m having the exact same problems as you and have about 35 router devices and only 3-4 end devices in my network. My router devices are sockets, dimmers, thermostats and switches from ELKO, and I’m using the ELKO Smart app for Homey Pro. Everything seems to work flawlessly up to 10-15 devices, but after that when adding more devices the network starts crashing at a frequency proportional to the number of added devices it seems like.
After talking with Homey Support and providing a diagnostics report, they sent me a replacement Homey Pro hub because of faulty hardware. Unfortunately, after receiving the replacement, the exact same problem started happening.
I am thinking about grabbing a Raspberry Pi with a Zigbee dongle and going for a similar approach as you to see if it can fix my problem as well. Very pleased to see that there is a Zigbee2MQTT app for Homey if I want to keep using Homey Pro over Home Assistant.
