On our Reflection cruise last month (exactly the same itinerary) I often saw cleaners working on stairways (as I only use the stairs). MDR staff were indeed working very hard but never seemed understaffed to me. My wine glass was never empty and the food always piping hot.
Regarding trash, my biggest bugbear is the from those passengers that leave dirty plates, uneaten food, and half filled glasses outside their door on the floor overnight. So disrespectful to fellow guests and the poor staff that have to bend down to pick it up!