Implement LAN and SAT in a single-family house with a central server cabinet

Turn off WLAN on the Fritzbox. The hotspot from the Fritz cannot handle the functions or does not have them. (e.g. multiple wifis, Vlan....)

I believe that would be somewhat overdimensioned. Basically, it is enough for me if every PC can access the internet through the various connections in the house and every phone via the WLAN through my Fritzbox...

A simplified version should be possible, right?

It could then be expanded at any time later.

Own wifi for the children with protection features, time control, guest access, separate network for the office. Iot devices, possibly cameras... The Fritzbox in the steel costs does not bring you any joy. You are stuck on the slow 2.4ghz network. A small solution would be a cheap switch (with PoE) and one or two NanoHds. These can be configured via app even without a controller and will run. Vlans etc. simply won’t be available then. Fritzbox wifi should be turned off anyway.

The ideas from Rick2018 are good, but I would simplify it a bit.

- Depending on the internet connection (Vectoring, S-Vectoring, cable, fiber) a FritzBox that fits, but WLAN off. (not much will come out of the metal box anyway)
- One access point per floor for WLAN -> I would also take something from UniFi here. Controller is enough for setup if it runs on the PC. It doesn't have to run 24/7.
- A switch without POE with many ports (24/48).
- POE for only 2 devices via injectors, for more POE devices a small additional switch with 5 or 8 ports.
The switches can be from Unifi but also from other manufacturers. I find the GS1900 series (smart managed) from Zyxel quite OK. I have the GS1900-E myself. With a large POE switch always consider that there are fans installed that can be quite annoying. The small ones usually don't have a fan yet.

How should the telephone be implemented?

That sounds like a reasonable plan

How should the telephone be implemented?

Telephone also via the FritzBox.

[*]1-2 DECT mobile devices and then also

[*]any number of (initially probably only 1 or 2) stationary phones (which ones are best for that)

which I would plug into the Ethernet ports.

It would be great if I could integrate the door intercom system and thus avoid having an intercom on every floor.

The newer APs from Unifi can be set up with the app (which is basically also a controller). With one or two units and without using the functions, a controller on the computer makes little sense. I think enoausa is rather overwhelmed with that.

With the DECT phones, the question is how good the coverage is. Fritzbox is in a metal box. You might need repeaters. Unfortunately, I know many people who have problems with that. You can use your phone as a handset via the FritzFon app. It's also practical when you are on vacation. Connect to your home via VPN and then make calls in Germany for free. The phones that connect to the LAN are IP or SIP phones. Do you get the SIP data from your provider? These also need a power supply or POE. With multiple POE devices, it makes sense to consider a switch with POE. Depending on the manufacturer, the fans almost never run. I don't get the impression that you would push the network to its limits.

What kind of door station do you want? Some work via phone. Unfortunately, mostly through a cloud of the manufacturer, which would be a no-go for me. Alternatively, SIP telephone system. You can integrate both with Fritzfon and with SIP phones/handsets.