I sure would like to see the main cargo door open. Another aircraft maker was able to accomplish it with cockpit tablets on DC-6, Cessna 182T and others. This would really jump up the realism. I haven't tried loading cargo yet but if perhaps it got missed, adding graphic of cargo pallets interior and exterior views when door open would be great too. ::) :) ;)

I  think you can open CARGO doors. However, the catering truck and baggage carts will only come and connect to those doors. No other specific cargo loader is there.

You can use MSFS default options from ATC window to call upon the truck and baggage carts. There is also another  nice utility for pushback which includes the opening options of the doors. I use it. It is in flightsim.to