Which type of camera for the house entrance area?

Provide more details and we can help you. The solution with Synology is very convenient. Especially since you can also use the NAS as your own cloud, media server, data storage, Photostation, etc. There are also many guides available on the internet for this. Anyone who is somewhat tech-savvy can manage it. What kind of internet connection will you have?

Provide more details and we can help you. The solution with Synology is very convenient. Especially since you can also use the NAS as your own cloud, media server, data storage, Photostation, etc. There are also many tutorials available online for this. Anyone somewhat tech-savvy can manage it. What kind of internet connection will you have?

What details are needed to make it even more precise? Will have fiber optic 250/500 Mbps.

For example, a ds218+ or ds718+, 2 hard drives, a small UPS (with USB) and two extra camera licenses. Then the 4 cameras and that's it.

Take a look at the Dahua cameras. You can find some information about them in the KNX user forum. The price-performance ratio is said to be extremely good. Of course, not high-end. They should also be within your price range. I decided on the 5442 series. These are available in all kinds of designs and focal lengths...

As writes, NAS etc. along with that should be enough for playing around at the beginning

The easiest thing is a plan with the camera positions as well as the height at which they should be installed and the area to be monitored. Glasfaser von der Telekom? It’s about whether you get native dual-stack, meaning a public IPv4 address. Only then is it really fun (access from outside via VPN or directly to the NAS, cameras, PhotoStation...). However, you can also make do with Synology’s (slow) relay server or set up a port mapper.

The external network should be separated and the clients authenticated using certificates.

Which switch can you recommend for this? I am looking for a 24-port switch.