Q: why is running a cable across the house not an option?
it’s not length, since 30m should be enough for most mcmansions.
it’s not cost, since cables are fairly cheap. Cheapest option there is.
you run along wall edges, taking the long way if you have to. When crossing open areas, you lay a rubber cable protector over the top (or a strip of carpet with a gutter cut out underneath), to stop tripping and make it look nice.
I’ve run cables between floors, down stairs and such. Stairs make things easier, because you can run the cable across them without tripping anyone, or needing to cover them. You can wind through bannisters to avoid using tape too.
Also, you should only be running one cable, and putting a switch at the other end.