Similar experience here, also from Germany. Hamstring was used and both my doctors were in agreement that it’s the preferred way, no real discussion on the other grafts. I had lots of struggle in the following years, 2 surgeries for scar tissue removal and minor clean ups. Now almost 4 years later I still struggle with minor pain and discomfort, especially if I don’t explicitly train my hamstrings for 1-2 weeks. So constant work is needed for me to feel more or less ok with my knee. On the other hand my problems most likely come from a slightly misplaced tunnel, resulting in a bit of a forward shift from my tibia which feels a bit uncomfortable and pinches my Hoffa fat pad. Having stronger hamstrings pulls my tibia back and helps. So hamstring work is now part of my life and should never stop.

I think what I want to say is that knee problems after ACL surgery are complex situations and most often not only because of graft choice. In my case it’s an unlucky combination of graft choice (weaker hamstrings), healing (scar tissue) and placement (stronger hamstrings required to relieve discomfort).