What equipment is for resale value

One outlet on every floor and possibly also at the TVs. Normally, no one needs more.

That's already old building today.

If Bookstar is good enough for you, great, it wouldn’t be for me. LAN just works and you don’t have to mess around with the annoying WLAN.

Then I would rather repair the WLAN. I have never had a problem with it.

Somehow, I lack the temporal reference. Resale value in 30 years? Then you can’t convince anyone with LAN cables. The technical equipment will have long been monetarily and technically depreciated by then. Even KNX and the like. Home technology as well.

I think with gigabit network cables at all important points in the house (including TV) you are well equipped for the coming years.

I meant less cables or wireless, but rather the fundamental question "Each & Everything over IP" or "Home automation via a special bus system".