I love Steam's in-home streaming!You don't need an internet connection. Just need to be on the same network at home.
Latency over wifi is terrible, have one of those ethernet over power line adapters to my TV, works fine.
Controller or kb/m just needs to be connected to the device you using not on the pc once everything is setup.
I have a network cable connected to a Raspberry Pi 4 that is hidden behind the TV against the wall in the Living room. Nice minimalist setup and it runs great with Raspbian and the Linux Steam Link app.
I wish Microsoft had something like that for their gaming service. Had a free 3 months of Xbox game pass and the games just wouldn't seem to work with the control when I tried to play them using Steam link. Would have loved to play Ori & the Will of the Wisps in the living room. Such an amazing audio and visual experience.