If you have an average body length, I think there’s a good change you’ll end up sitting with your legs up in the air, folded over the seat in front of you. Don’t forget to apologize to the passenger in front. If you get served food, it’ll probably be a nice Cantonese dish.
Go to the city! When I am in a 4h+ layover and the city is close, we always visit the surroundings
That’s how I got to know Zurich in the first place :-)