In the full screen editor the graphics are very good, but in the packaging there is a problem in full screen

In the editor of UE4 VERSION 4.21 with cinematic quality and full screen my computer runs it very well, the problem begins when I package my project to make tests, in Windowed mode it looks very good but in full screen it is observed as if the image loses signal only to the rapid movement of the camera and by keeping it motionless the quality returns, this is too annoying and I can not find an answer … can you help me? I explain that I have a graphics menu and even with the lowest one having full screen the same thing happens

Here is my suggestion
You can run it in Editor with standalone game mode, full screen it and using “stat unit” to see the Game and Draw time.
standalone game mode might give you more options to slove the problem