Sounds like you just had a bad experience at a disgruntled airline. Base changes or aircraft changes can solve that. If you live in the NE at DL, there are plenty of choices and bases. You moving to MIA shows you made a change for the better. Good for you, but not every airline has the same trips---and you neglected to mention that. Your trips sucked because your airline had them, and you stayed there for 4 years. That was your decision. Another pilot might have taken your spot and loves it.
Not a disgruntled airline problem, but rather a disgruntled long-haul flying problem. Just pointing out that many prospective major airline pilots on this board have no desire to do that kind of flying, for the reasons I listed.
Glad you enjoy it, and glad those senior to me enjoy it.