iPhone 8 Camera not focusing even after two replaces

So, I bought an iPhone 8 with a replaced screen, a battery of 78% battery life and a camera that was blurry on the right edge and wasn't focusing too, I made a decision that I want to repair him. One camera I bought from AliExpress for 12€ and a second one from a local shop there for 29,99€. They are high quality and I tried them both but they're not focusing even after resetting all data and settings, I tried it through recovery mode either, I read that I should try factory reset through DFU mode but while replacing the battery I had to corrupt a cable on Volume down button because the button isn't working now and I don't know how to get iPhone 8 into DFU mode without working Volume down button.

Even after all of this, the camera isn't focusing and take good photos only from near. I was thinking about buying an JC V1S programmer so I could try installing new firmware into camera but I can't say if the camera that came in the iPhone at first is genuine and neither I don't know if it could help me.

I'm still working on that how could I solve this problem so I will be glad for your help.