The phone has been pretty fluid and responsive for me, but I've noticed jankiness when using several apps. Here are two examples:
1. When swiping to the left from the home screen to access the Google feed
2. When swiping to the left from Instagram home screen to record a Story, and when swiping to the right from the same place to access Direct Messages
To those reading, please feel free to add to this thread if you experience similar issues when using the phone.
Please see if this helps. Enable developer mode by locating the Build number in your Settings menu and tapping it multiple times. Then try reducing the three animation scale values from 1x to .5x. Worth a try...