Zigbee network less reliable after migrating from SONOFF-P to ZBT-2 (Zigbee2MQTT)

[dark tinsel]

I have 63 devices on my zigbee network. 40 of which are routers. My Home Assistant machine is in the top floor of my 3 floor home, and I've put the ZBT-2 pretty much exactly where the SONOFF dongle-P was.
I migrated the network using the silabs flasher utility to set the ZBT-2's IEEE coordinator address to that of the old dongle and most things have been absolutely fine.

But not everything, unfortunately. Even after a couple of weeks, things don't seem to have settled into a reasonable state, and at any given moment there's usually 3-5 devices showing as Offline. I've been resetting and re-pairing those devices when I check in again every few days, but I don't seem to be able to arrive at a stable state, which is a real shame because it was very solid before (and therefore I had no reason to do the migration other than wanting to support Nabu Casa).

I'm not really sure how to debug this sort of situation, because I've never encountered it before. I would appreciate any hints/suggestions of what I should be looking at.

[hollow mist]

Without knowing if there is a specific part of the network or if it is more of a "random" problem with offline devices, I'd first try to see if the propagation from the ZBT-2 antenna is a factor.

The first and easisest thing I would try is to change the orientation of the ZBT-2. It appears the radiation pattern is doughnut shaped, imagine threading a huge doughnut over the antenna. This could mean that you are less likely to have good coverage with other floors. So if you place the antenna at a 90-degree angle to a wall and imagine the doughnut to extend out towards your lower two floors. Try it and see if it makes any difference. As usual, try to have as few solids as possible in the path of the radio signals, especially metal, concrete and bricks.

[dark tinsel]

I actually did try that a day or two ago and it seems to have made no difference, unfortunately

At this point I feel like I either rebuild the mesh from scratch, or just migrate back to the Sonoff dongle, and I’m leaning strongly towards the latter.

[dark tinsel]

I also feel like I’m the only person seeing this, everyone else seems to be having a lovely time with their ZBT-2 from what I can find!

[dark tinsel]

https://community.home-assistant.io/t/the-best-gets-better-home-assistant-connect-zbt-2/953028/177

someone else seeing the same kind of behaviour

[granite topaz]

I'm seeing the exact same behavior that the user that posted this is, except I came from a ZBT-1. Before, I only had 1 or two devices that would take a little longer to control, but aside from that, everything worked great. Now frequently I'll lose connection to my zigbee devices as well as my ESPHome devices. Were you able to find any resolutions?

[dark tinsel]

Nope, I migrated back to my Sonoff dongle and it’s been fine.