filter - OK
ductwork - may be problem. If pressure drops to zero due to restriction, CFM will also drop. It takes pressure to move air mass.
evap coil - you need to verify it's clean, especially since you recently moved in & don't know the history.
ductwork - may be problem. If pressure drops to zero due to restriction, CFM will also drop. It takes pressure to move air mass.
evap coil - you need to verify it's clean, especially since you recently moved in & don't know the history.