Hi @jean_bruder 
On my side I push 100% local solutions as much as possible, and that’s what I apply on my personal setup.
As @McFlyPartages said very well, the recommended protocol is Zigbee for all low-bandwidth devices (smart plug, bulb, sensor, etc…)
For audio and video streams (camera and speakers), it’s Wi‑Fi with open protocols (RTSP for cameras in particular)
That’s what I applied at home, I have 37 Zigbee devices in my apartment (EVERYTHING is Zigbee: switch, bulb, etc… :D), controlled locally with Zigbee2mqtt.
Tuya should really be avoided, it’s the worst in terms of cloud: they change the rules of the game for developers quite regularly, it’s the best way to end up unable to turn on your lights because the Chinese cloud changed its API ^^
We integrated it into Gladys anyway to attract users, but I don’t personally recommend it.
For AI, I disagree with what’s being said: currently, to run AI that rivals ChatGPT you need an ultra‑powerful machine:
- Nobody here has that hardware (Seriously, who would want to put more than €1000 into their Gladys hardware setup?)
- In terms of power consumption, it would be ridiculous for everyone to have the computing power of the AI running at home to be used a few times per day, when that power could be pooled among all Gladys users as is currently done. The goal of home automation is also to save energy.
- The project’s philosophy remains to offer something for the general public, easily usable without configuration. For now, ChatGPT via the cloud is the only one to fulfill that promise.
For the speech synthesis part, if someone finds a local French speech synthesis that rivals what we have in the cloud, I would be the first to integrate it into Gladys. For now, it doesn’t exist 
Note: my opinion on AI is based on the state of the art in December 2024; it may well be outdated in 3 weeks!
For voice assistants, Google and Amazon have chosen to go through the cloud; unfortunately, for someone who wants to use their solutions there’s no choice, you have to be realistic 