Indeed, Zigbee can at the beginning be very finicky and demanding if not set up optimally for your specific environment, so for starters, I always suggest being sure to add a few good Zigbee Router devices (as having many good Zigbee Router devices being available at all time is the main key to a stable Zigbee network mesh), and taking some basic actions to avoid interference is important too → Zigbee networks: how to guide for avoiding interference and optimize for getting better range + coverage
Using newer Zigbee Coordinator adapters with later firmware can also resolve or hide many issues, though they may also introduce new bugs, so it can be a gamble when choosing to use more mature firmware or the latest cutting-edge firmware. Here experimenting it really the only option as it will depend on what exact devices you have and how well the firmware on those devices work with different Zigbee Coordinator firmware.
Anyway, for better or worse, a great Zigbee network mesh set up does initially require some excessive care, precision, and attentive effort for optimal operation in the long run. However once you have those basics in place, then it should just work automagically, (unless you add some rouge device with buggy firmware to your Zigbee network mesh that do not pass along all messages from its neighbour devices).