New Building Doorbell System - Experiences

Ah ok, so far a 24-port switch is planned for the utility room. Do they generally have PoE functionality or do I need to pay special attention to that?

No, not all of them generally have PoE functions. However, if you search for PoE switches, you will find suitable options. As Araknis already mentioned, it is worth considering supplying the PoE-relevant devices (+ e.g. access points?) separately from the regular switch. So possibly with a smaller PoE switch in addition? The power consumption (standby) of PoE-capable switches should not be underestimated, so it might be worth taking a closer look here.

I was already planning to install a switch with 24, possibly even 32 ports in the utility room. So I could then connect a "smaller" PoE switch to it and run the patch cables from the doorbell and indoor stations to it?

One more question about the VDM10: There is no separate chime. Is the doorbell melody still easily heard in the hallway?

Is there maybe someone here who also uses the Balter EVO? I would also be interested in your experiences with it, it might also be an option.

I also wanted to take a look at the products from Mathfel.

I was already planning to install a switch with 24, possibly even 32 ports in the utility room. So could I then connect a "smaller" PoE switch to it and run the patch cables for the doorbell and indoor stations to that?

Yes. Personally, I would keep it at 24 and additionally use an 8-port (?) PoE-capable switch for a small cost and lower power consumption.

One more question about the VDM10: There is no separate chime. Is the doorbell melody still audible well in the hallway?

I had originally thought about this too. The pre-installed doorbell melodies did not impress me, so I added 2-3 of my own. Depending on the "sound," these are quite loud and can be heard throughout the house :)
Ours, for example, is installed in the kitchen area, and I assumed that just based on the volume, I would need at least one more upstairs. Although I will install the latter later, the volume of the one on the ground floor is sufficient to be noticed upstairs as well.
Accordingly, it is "loud" downstairs, but you get used to it :) ... adjustments will follow.

My recommendation would be a passively cooled PoE switch.

When using the POE switch, pay attention to the POE standard to ensure that the switch and clients are compatible and also consider the entire POE budget.

We are currently in the shell construction phase and have had similar thoughts regarding the electrical planning. At the moment, we have decided to first install a regular doorbell and lay an additional LAN cable outside for it. Also PoE.

This might not be for everyone, but I plan to manage the house anyway via Home-Assistant & Homebridge and since everyone in the household uses iPhones, it will probably be a HomeKit doorbell.
If someone rings, everyone automatically receives a notification on their phone. Also, all HomePods in the house ring and the camera image is displayed on the AppleTV if the TV is on. The door can then also be opened via Siri or the phone.

Of course, this is only for people who are in the Apple universe, but definitely an attractive solution then.