Until a few days ago zigbee green power was not supported in zha/zigpy. It now seems to be merged. I'm not sure if zigpy supports the same amount of devices as zigbee2mqtt
I found ZHA to be suffering from severe doc rot around OTA updates and a few other edge features, and that devices that just worked with zigbee2mqtt were unpairable or unstable with ZHA. I gave up after 3 months of almost daily effort and went back to zigbee2mqtt, where I had immediate stability and almost zero effort.
for me that happened because of interference. I switched from a Conbee II to a Sonoff Dongle-P and that already helped tremendously. That new dongle is way more stable for me. Also I changed my wifi and Zigbee channels and reduced the transmit power for less interference. Since than my Zigbee netwerk is really stable.
Updating the firmware in my sonoff dongle-p made a massive difference in network stability. It's a bit of a mission to get the update installed but was well worth it.
[1] https://www.home-assistant.io/integrations/zha