Just yesterday Koen Kanters, the creator of Zigbee2MQTT, released a new firmware version 20221226 for a bunch of ZigBee coordinators.
According to release notes, it has improved performance/reliability for a larger network (100+ devices) – the thing a lot of us were waiting for.
The binaries can be downloaded from GitHub. Just make sure you choose the right firmware for your adapter, otherwise it can be bricked.
There are a lot of useful links on ZigBee coordinators/routers flashing available in Zigbee2MQTT documentation.