You didn’t say if you were deck or engine. If you are in deck:
Go to ammo ships, Lewis & Clark class (T-AKE). Ammo experience is hard to get. Plus those ships do enough fuel that getting your PIC signed off is no problem. Modern plant and propulsion, lots of arrivals/ departures to load cargo, usually a pair of helos on a deployment and those are modern and comfortable, unlike the old Navy T-AEs.
Don’t go to an oiler. Those do no ammo, some cargo, and are so outdated what you learn there about bunkering would make for a good historical book. Tanker trash.
The other classes of ships at MSC are pidgin holes - except for general navigation what you learn on those have little application to other ships.