LAN and Wi-Fi "devices" per floor?

The question is, what advantages does the POE solution have apart from saving a few loose cables? Is it faster or more energy-efficient?

No, it is definitely not better. But you do save the power cables.

Thank you very much, karl.jonas, for the recent answers. Regarding devices, I can then take a look or test...

I have a question right away. In principle, I understand the structure of a home network. But why do photos of patch panels, for example, show 16 patched LAN cables plugged in at the back, and only, for example, 5 LAN cables plugged into the switch ports? Are those only the ports that require Poe(+), and the rest are powered through it? Assuming I have a 24-port patch panel, then I wouldn't even need a 24-port switch, right? For 2 access points and 2 cameras plus some spare capacity, would one with 8 or 12 ports be sufficient?! Or what else is powered with Poe(+)?

No, every connection must go into the switch. The patch panel is nothing more than the organized collection of cable ends. If the cable end is not electrically connected (through the switch), then there is no data at the other end (LAN socket). PoE has nothing to do with this.

So if you see photos - wherever that may be, where your example is the "rule" - then the unconnected ports are simply dead. Some only connect the ports that are actually needed at the moment and the rest is reserved for later. But that actually doesn’t make sense. Because if I want to use such a socket, I first have to run to the basement and patch the connection.

But it actually doesn't make any sense. Because if I want to use such a socket, I first have to run down to the basement and patch the connection.

The photos may not be from private houses, but from administrative or commercial buildings. It often makes sense here to terminate all connection sockets at the patch panel (at the back), and then, if necessary, connect the respective socket to the switch (and thus to the LAN) - or not. This way, it can be prevented that someone quickly plugs into the network in an empty office or a public space. And if the need arises, it is much more comfortable to plug the patch cable in the server room than to fiddle around with the floor socket.

But why do photos of patch panels show, for example, 16 patched LAN cables plugged in at the back, but only, for example, 5 LAN cables in the switch ports?

In your example, apparently only five of sixteen potential endpoints are actually used, i.e. only five of the sixteen sockets have users.

Assuming I have a 24-port patch panel, then I wouldn't need a 24-port switch, right?

The number of ports on the patch panel is always greater than or equal to those on the switches in general, and certainly greater than the PoE-powered switch ports. If an office has four corners but only three desks, only three workers use their computers, but the fourth corner is also wired, and this cabling at the server room end is not just thrown somewhere. Therefore, temporarily unused ports on the panel are the rule. A switch is an electronic "Fräulein vom Amt" and serves all available workplaces - so none are held in reserve. And injectors for PoE are sometimes only available on part of a switch’s ports because not every endpoint requires PoE. Power over Ethernet (meaning the modulation of power supply for device operation onto the line used for data exchange) is mainly needed where, in an office telephone system, a separate power adapter cable should not be used for every IP phone. The plug-in power supplies are comparably cheap s**t and are also often avoided fire hazards.

The patch panel is nothing other than the orderly collection of cable ends.

A plug-terminated orderly collection, to be more precise.

This can prevent someone from quickly plugging into the network in an empty office or public space.

The system administrator prevents this through permissions, which are by no means related to the use of the sockets.