Hi everyone, first post after 2 years reading.
I am a DIYer from Italy, I worked 2 years on openhab in my home.
I am very close to have an electromagnetic free home running mostly on photovoltaic and wood from the garden. I had a small company aimed to provide energy saving and comfort in houses but we used plcs mainly.
In my house I use ethernet for almost anything, I use arduino uno, due, esp32 with ethernet shields. OH is running on raspberry 3b+.
I realized I cannot wire all the temperature, door sensors and switches I need so I decided to accept zwave or zigbee. The house is a long rectangle so lot of walls.
I’d like zigbee xiaomi temp sensors because I appreciate barometric pressure (I have to keep inside pressure slightly over outside). BUT xiaomi gateway is wireless, wifi is off most of the time and I wish an easy system, after 2 years of developing I am tired to debugging things, really, the idea of zigbee2mqtt make me nervous maybe a prejudice.
Also there is great confusion about zwave zwave+ zigbee3.0.
I read a lot and I am confused maybe someone knows a solution to have a button and a wired gateway with door, temp/humid sensors and some switch that is almost plug and play.
barometric pressure is good plus but I can do it implementing bmp280 on existing diy devices.
Thanks for the time dedicated to this long post and for your reply if you have some help for me.
I I’d like a plug n play solution, I wish to avoid study, understand, try and finally see it work. But as I told it my be a prejudice, mainly because nothing worked immediately until now. If I have to invest time on those sensors I prefer to wire everyhing and use esp32 as I did for everything else.
My home is wired for the purpose of not having electromagnetic waves and security/privacy. I don’t even use AC current. Also by night I only go on 12V. For the same reasons I keep wifi off most of the time, I have a routine that keeps it off while I sleep for example. zigbee and zwave only emits when sending values, once every minutes, and I will have the gateway on the garage so I can accept it to be on h24.
Really I can use zigbee binding with xiaomi devices and no zigbee2mqtt?
what wired gateway would I use?
I’am in Italy, please tell me more, should I stay away from devices from china or usa?
I don’t even knew that, can someone point me to a wired plug an play solution either zig or zwave?
My skepticism is is due to this thread and other similar https://community.openhab.org/t/xiaomi-temperature-and-humidity-sensor/69053/7
I would go with zigbee if I can buy a wired (or usb wiring a usb cable) gateway that works with the zigbee binding with squared xiaomi sensors without problems. Can’t find someone that describes a working solution. I got the impression that zigbee gateways are not all the same, people with different gateways reports different behaviours. Also the antenna is different and I need some range, is there a comparison between gateways or at least some advice?
UPDATE: wired gateway+button+pressure
I found a zigbee button (hue) if someone can help about a usb or ethernet zig stick that works also with xiaomi aqara sqared temperature sensors with zigbee binding I (we) found the solution.
Just for confirmation…those zigbee devices will work without internet when paired with oh2?
and I wish an easy system, after 2 years of developing I am tired to debugging things, really, the idea of zigbee2mqtt make me nervous 
maybe a prejudice.