Being junior anything at FedEx brings a quality of life significantly lower than most enjoy. If you are really junior make sure you have a face mask and gloves for preflights in the winter. You better able to sleep during the day too.
Some very junior MD-11 crewmembers have to go to the SIM to get landings. Does anyone know about the 777 folks?
That's why we have some very senior FOs and SOs.
Since our flying focuses on international your upgrade opportunities will be fewer if you don't like HKG.