Before you start troubleshooting the software side any further, be sure to set up hardware properly first.
Zigbee and especially the Zigbee Coordinator are known to be very susceptible to Radio Frequency Interference (RFI) / Electromagnetic interference (EMI) caused by different signal interfering sources, so all the tips to try to reduce interference are extremely important to follow even if they may sound silly.
As standard with any Zigbee Coordinator adapter today, try to follow all the best practice tips and tricks posted in PR https://github.com/home-assistant/home-assistant.io/pull/18864 as well as those here https://www.home-assistant.io/integrations/zha#best-practices-to-avoid-pairingconnection-difficulties
Short summary:
- Upgrade to the latest firmware on the Zigbee Coordinator adapter (whichever adapter you have).
- Connect the Zigbee Coordinator adapter to a long USB extension cable to get it a bit way.
- Be sure that Zigbee Coordinator adapter is connected to USB 2.0 port (or via USB 2.0 hub).
- Shield any computers and USB 3.0 peripherals like hard drives by using metal enclosures.
- Make sure Zigbee Coordinator adapter and devices is not close to WiFi router or access-points.
- Zigbee devices do not have long-range (or good radio signal penetration) on their own so begin by successively adding more mains-powered Zigbee Router devices (a.k.a. Zigbee signal-repeaters/range-extenders) closer to the Zigbee Coordinator adapter and then in each room building outwards to form a stable Zigbee network mesh before adding devices further way.
- Afting adding mains-powered Zigbee Router devices pair all the other devices where you plan to have them permanently installed and do not move them around afterwards.
- If still have issues change Wi-Fi channel(s) on your WiFi router or access-points to do not conflict with Zigbee → https://www.metageek.com/training/resources/zigbee-wifi-coexistence/
PS: Appreciate if tumbs up PR → https://github.com/home-assistant/home-assistant.io/pull/18864