When all settings are set to the highest, there is no significant fluctuation in frame rate during low and high altitude flights. However, this slow movement issue occurs on aircraft such as the A350 and 787, with the A350 being more complex and more precisely on a certain runway at some large airports, as it moves abnormally slowly when taking off on certain runways at EGLL and KJFK
I have taken a picture of this, which shows that the plane's speed is as high as 180 knots, but the runway is not yet halfway through