I cycled at PFC, six donor egg cycles in total; all BFNs or miscarriage. I finally changed to a clinic in the US with high success rates, and got pregnant the first time with twins and had a successful live birth
It seems many here turn to immune testing, gluten free diets, all that. I looked into all those things too as the failed cycles at PFC convinced me for a while that I had some mysterious problem. But the "problem" wasn't me.
Clinics in the US publish stats from all their cycles in sart.org. How many cycles were done at that clinic, how many resulted in pregnancy, how many did not. I don't know any similar published stats from clinics in Europe. It seems with European clinics, you just have to go by whatever they claim their success rates are.
Best wishes.