Best retrofit smart home new build

1. it depends if it is possible to do it myself I would do it myself 2. rather less 3. I would still have to check but basically you can do everything step by step when retrofitting (I would not set a limit at first and see where you would end up and what you could still delay) 4. living room and dining room but that actually works quite well with soundbar and speakers 5. we are only getting a normal doorbell and can then add everything later so yes we are free

for the video doorbell I need to know beforehand which one I am taking so that I can have the necessary connections prepared for this model

1. it depends, if it's possible to do it myself I would do it myself 2. rather not

Take a look at ioBroker or Home Assistant and their setup. If you feel confident, that would be an option. Otherwise, you have to take something "ready-made," e.g. OPUS on HomeKit or Google Home.

4. living room and dining room but actually that works quite well with soundbar and speakers

If you have no further requirements (e.g. lighting scenarios or connecting blind positions with TV/audio, etc.) then just leave it as it is.

5. we are only getting a normal doorbell and can build everything on later so yes we are free for that for the video doorbell I need to know beforehand which one I will take so that I can have the necessary connections prepared for this model

Definitely have LAN installed. Almost everything can be mapped through it. Given your conditions, the video intercom will probably work more as a standalone system and not be integrated into the building control. So also think about the indoor video station! Having it only on the app is possible but gets annoying over time.

I have KNX but only because the electrician cooperated with me. Otherwise, I would have installed Homematic. My brother is currently retrofitting it and actually it can do almost everything that people understand as smart. Lights, blinds, heating, etc...

Possibly Loxone Miniserver Go? There is a new intercom system recently. Audiserver is also available. Retrofitting and connecting roller shutters with Shellys is also possible. The app is quite nice.

Is there a good retrofit smart home?
We bought a semi-detached house as a new build from the developer.
The electrician waved off the KNX topic and said he doesn't know anything about it, we don't do that.

I am renewing my suggestion from your other thread: think kindly about enduring, during the time you search more relaxedly for an optimal property in the middle house, without large-scale upgrades. You can also go to work in a Polo; it doesn't necessarily have to be retrofitted with a V8 triturbo.
Only the coffin is the last house that you can no longer change.

By the way, congratulations on an electrician who knows his limits instead of leaving ruins of his bungling.

I think you can learn how to use Iobroker or homeassistent. The house shall not become a temporary home; we want to live in it for a long time, about 30-40 years. We want to adapt the house as well as possible, and if something cannot be retrofitted or installed by the builder, then that's just how it is, and we have to live with it. I am trying to find out how we can retrofit the smart home as well as possible.