Which router for our new building?

Well, Araknis only writes about "occupied" switch ports and not about those actually used.

If Arkanis uses various cameras, quite a few could already add up.

I still don't know how many devices you want to connect. I've counted 3 APs, 2 PCs, 4 for TV, 1 for router... makes 10. Available ports don’t count!

Just get something like a Netgear GS116LP PoE switch with 16 ports. Compact, fanless (low maintenance, energy-saving, silent!) and affordable. When the day comes that it's no longer enough, you can upgrade.

If Arkanis uses several cameras, something could add up there.

Exactly. A few more access points, doorbell, displays... it already adds up and I'm still far from the upper limit of the possibilities.

Well, Araknis only talks about "occupied" switch ports and not about actually used ones.

Occupied means used, i.e. a device is connected.