LAN, WLAN, bandwidths and contents?

No one needs 4K for film and television at home (even in the future).

Need? You really don’t need a TV at all.

But at 75 inches and 3.5 meters distance, there is a visible difference between 2K and 4K. Nothing essential, but you also didn’t really need the upgrade to 2K, you could see something before anyway...

(I think Wonder Woman was the movie we watched in UHD. Awesome. Although it’s simply a good movie.)

No, I deliberately wrote "need" in the sense of "it's useless." It is simply not possible to see a difference without binoculars. --> Wikipedia "resolution".

However, your example is actually right on the edge, where full HD (for people with good eyesight) might be a bit too little. In 98% of households, though, you will encounter a larger distance on the one hand and a smaller diagonal on the other. Therefore, I'll cheekily stick to my opinion.

But please don't misunderstand me: I am a quality enthusiast myself and enjoy technical innovations. The desire for more resolution is actually disadvantageous for almost all applications, as it takes away capacity for higher dynamic range and decent audio tracks, often without providing an added benefit because the eyes are simply too poor.
4K is something fine. For consoles - if they ever get fast enough - and for PC games it's a must. But then I stick very close to the screen. For movies, it would be much more important now to finally move away from the slow 24fps and define HDR as the standard.

And regarding streams, unfortunately it is still the case that a Blu-ray offers better picture AND better sound than almost all 4K streams from the internet.

Only it also stutters for you.

In a good router I can set QoS (Quality of Service) so that my devices enjoy higher priority/bandwidth than the kids'. Alternatively, modern routers can set up multiple Wi-Fi networks: 2.4 GHz for guests/kids with bandwidth limitation and forced shutdown at night, and 5 GHz for the parents. Nothing stutters there (at least for me) and the kids inevitably find another real-life activity when the internet is slow again.

But with 75 inches and 3.5m distance there is a visible difference between 2K and 4K.

The higher the resolution, the closer you need to sit to see all the details --> It’s pointless to sit too far from the 4K TV if the eye only sees the fine details blurred; then it looks the same as Full HD. 10-bit HDR makes sense for richer colors, 4K resolution only to a limited extent depending on the source input and distance to the screen. The "widest" rule of thumb for UHD recommends screen * 1.5 (for 75 inches this would be 2.85m distance), other manufacturers recommend even only 1.5m distance for 75 inches).

Edit: humanity doesn’t need more than 24fps since the eye/brain simply can’t process more

It's a bit binary here. As if it were about "LAN yes" or "LAN no."

Applications with higher bandwidth requirements should preferably be supplied with cable, the rest can nicely do without it. You can save yourself the socket for the coffee machine or the fridge, a waste of money.

About Evolith: Your kids are apparently still small. But that will change. And when your son always hangs in front of the console and always wants to play World of Warcraft and stuff, then you don’t give him a LAN socket, but you take him aside and say, my boy, I see you are a hero, a fighter. We, Dad and I, therefore want to send you to the Bundeswehr so that you can defend our fatherland in Mali or at the Horn of Africa, we will be proud of you, and if you fall for homeland and fatherland, we will cry, but also honor you. Boy, how do you like that? And then let him come... Karsten

I have never read bigger nonsense.