I haven't needed this since before Covid-19, but the Yotel hotel in terminal 4
avoids needing a bus. Rooms are closed in pods. Either double deck for 2
or an almost double size mattress. From the Yotel in termianl 4 the free
train is at worst 15 minutes to terminal 5. The pods are cramped.
For me the local Japanese hotel rooms were very pleasant.