Ohh I think I misunderstood your original post - When you say "I cannot really wear my office outfits at home because there is at least 5C temperatures difference between my office and home. So at home I *don’t* need warm layers and scarves which limits possibilities." that means your home is *warmer* than the office, not colder, right?
In that case sorry, just disregard my previous advice - I thought you were asking how to have variety in *winter* outfits, lol! As for cooler outfits, I agree that lighter weight tops would help - any tank tops that you could wear under an open button-down shirt, for example? What about dresses or skirts? Or even rolling up lighter weight trousers at the ankles for some airflow? If you have any lighter weight scarves, they could be fun to drape too, no? Otherwise maybe choose just one accessory to wear with your outfit (doesn't have to be a scarf - I originally suggested nail polish because it doesn't get in the way of keyboard typing, unlike a bracelet or ring lol)