I completely sympathize with you and am sorry your experience in Prae was not good. Unfortunately this issue is a catch 22. On the one hand no one was doing old content like that and someone like you who is just starting to get into FF14 and run the final ARR content would literally never be able to queue up and actually finish the main story leaving you pretty much stuck not being able to get into Heavensward content. This is why SE decided to make it rewarding i.e. XP for leveling or Verity for level 70 classes, so that people in your situation would be able to get these things done.