Viktor, I don't have an answer, but I understand the feeling of duty and failure together. For us, "going back" is not only our decision, it depends on things far bigger than our family. What I've learned is that it doesn't have to be a single moment of deciding. We talk about it every few months, honestly, with our daughter too, and the answer can change. Maybe try something in between first, like a longer stay with your parents, before deciding forever.
Three years in Germany. Good job, my daughter happy at school. But my parents in Bulgaria are getting older, and my father's health is not good. I'm starting to think about going back, and I don't know how to decide. It feels like failure and like duty at the same time. For those who went back, or decided not to: how did you know?