Everything already exists and everything works, nonsense intelligent, the future is here, just not reached by many, often due to lack of information and willingness for something new on the part of [GÜ's] and [Elis]...
Just lamps, roller shutters, voice control, and garden irrigation are 4 things...
Apart from that, automating individual areas/systems is not smart... it only becomes smart when everything is connected and listens to the residents and acts and reacts accordingly...
Well, the last two: lamps that turn on slightly at night when I look at them and wireless sensors without their own power supply. I have written everything about the other four: I have lamps, shutters don't suit me, offline voice control doesn't exist, and I do my own garden watering.
... and wireless sensors without their own power supply
Take a look at EnOcean technology. There, sensors are operated without cables or batteries via energy harvesting (e.g., through solar or kinetic energy).
Offline voice control does not exist
It does - the only question is whether it fits your "solution".
Examples would be SynOhr in the KNX system. Or Alexa, which is approved and can be installed on a Raspberry.