You also need to allocate some monthly time for maintenance - small or bigger updates, new devices, security issues... it's not a one-time project but an open-ended job.
Which is why I don't have anything automated in my house. I have kids to raise, I have trouble finding time for any hobbies at all. I don't have time to take on the automate my house hobby.
I do recommend getting at least one Hue bulb for the kids; you can entertain them for a solid half hour by setting the bulb to automatically change colors and turning the rest of the lights off.
I have a Hue sphere bought like 10 years ago(?) and it was fun for a while - a year even - to prepare for sleep in slowly changing lights. Nowadays it just gathers dust in a corner while still looking cool, ain't nobody got time for that anymore.
Why? HA can operate entirely offline without access to the internet. You aren't suppose to expose it to the internet, you can't but they advise against it.
In that configuration you only need to update the software when it no longer meets your needs. If it's working then there's no need to update it.
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.