Why are you posting on here if you don’t have an issue ? I don’t get it ?
Well I have two iPhone XS Max and two iPhone X and none of them are displaying the behavior you keep claiming to see, they each suffered other issues that apple support saw fit to replace the devices.
I asked for evidence of your claim, one video was posted, titled stuttergate, dated 5 months ago and keeps getting reposted. The video is of poor quality and does not show what you say is happening to your iPhone.
The behavior is being labeled as a stutter, a micro stutter, an animation delay, and dropped frames by different posters. However each are very different things, they aren’t the same.
There are other posters as well claiming their iPhones do not exhibit the behavior your describing and cannot see what the video is suppose to reveal, its just some creepy guy saying there is a stutter.
And from what i read it appears as though the few posters on the thread that are exhibiting said behavior, all have low post counts and have been posting predominately or entirely in this one thread.
It’s questionable to say the least.