Lock animation issue

Hello there. I just switched to iPhone 13 and I noticed that when I lock the screen, the animation is not smooth at all (it feels like the screen goes dark in 2 short phases) and it’s sometimes quite slow compared to other devices with iOS 16.2 I’ve tried. I turned off the Apple Pay double-click and all the accessibility shortcuts are turned off as well, so that’s not the problem. In the dark, the lock animation disappears altogether as if Reduce Motion was on. Why does this happen? Can I fix it somehow?