I spent the day reading Zigbee and repeater topics.
I still have many doubts.
I was having problems with the zigbee network, some sensors were not communicating well.
Once connected they would work a couple of days and then stop.
Or after a power failure they would not connect anymore.
Adding two ikea repeaters I solved for the sensors of the stairs.
But I continue to have problems with the sensors in the garage.
I have had the repeaters on for 4 days now but they do not repeat.
The main problem is on the SW3 (in garage) switch, it only connects to HE and nothing else.
If it drops voltage it won't connect anymore, and it still works 1 time out of 5. IK2 has been there for days but no one connects to it.
Also s4 connects to B4 or B5 (now it is connected to B7... What?) but not to IK2.
Help me to understand
I tried turning off for 20 minutes HE did not yield any results.
Not unusual for Zigbee or Z-Wave mesh networks. The devices have no concept of physical proximity or position on a floor plan. At a high level they try and select the best routes based on signal quality measurements. The result is you see routes or paths that make no sense whatsoever, and that is normal and nothing you can do about it. Best is just blanket areas with either main powered devices and/or repeaters. Give the network the most opportunities to select a good physical path, but be prepared when they don't.
Also note sometimes it takes days, if not weeks, for the mesh to full settle in and optimize.
Having a repeater very close to your HE hub is a good design idea as hopefully more devices will router through it. The reason being is a repeater will handle repeating the commands to other repeaters and devices on the mesh, freeing up the radio on the HE.
I suspect this is a good part of your issue. You will see on the forum that bulbs have a reputation of being very bad repeaters. For this reason, people that have Zigbee bulbs typically pair them with another repeater or with the Philipps Hue Hub. Sengled are the recommended bulbs as they are not repeaters so don’t cause the issues. I personally have all my non-Sengled bulbs paired with the Hue Hub, which is then connected to Hubitat.
Just my 2 cents. I would put a outlet-repeater in every room and 2 if the room is real large. I use sylvania repeaters and sylvania bulbs made by Ledvance. The bulbs do repeat but they are never powered off and work very well. Mesh is stable and I don’t have any devices dropping off. I have two repeaters at the rear of the house that connect to the devices in the garage which is 80’ away. Everything works great. I have only 1 hub and about 40 plus devices.