IPHONE X GHOST TOUCH

I have an iPhoneX for 6 months now. Extreme happy, but after updating it to 11.2 the ghost touch phenomen started here. It Is very haitfull. He opens apps, delete important mail, delete pictures, close and open apps at random. I called the applecenter and they checked my hardware. Nothing found. I did every possible reboot, clean install and all the other stuff you could think of. I did not let my phone fall and even removed the extra front and backcover. Now they say I have to make ann appointment again but then I lose my phone for two weeks. But in my high possition I can not afford that. They dont have extras so I’m in big trouble. I can not understand that while I am a huge fan of apple and it product, they wont help me. It is still in garante of for more then 1000 euro I expect a phone that works. I am considdering to switch to android and be sure that my heart will bleed then. Are there more people who has the same problem? Or a simple fix?