ZX9R (ZX900EF) front brake rubbed

Hello Kawa-Gemeinde, My Kawasaki ZX9R rubs when braking at the front quite strongly. First I thought about the brake discs and changed them. I used high-quality accessories brake discs. Of course I also changed the brake blocks. This has not done anything. The motorcycle was then in the workshop and there the problem was also tried to solve. The front wheel rim was measured and the brake discs of course also. Then the kom plete fork removed and also tested for deformation. The steering head bearing was renewed and a new tire was mounted. All this did nothing and the rubbing during braking remained. Conclusion: Workshop unsuspecting and me also and 800€ poorer . Does anyone have an idea?