I do a simple screen recording using quicktime player. I open the video in quicktime player and it looks great.I import it into after effects and I can't preview the video withought signifigant distortions. I'm using a 2018 macbookpro with ssd, upgrade gpu and 16gb ram. Also separate ssd for media/disk cache
Any thoughts would be appreciated
including a screen record demonstrating how much better quicktime handles the video compared to after effects
Your comp panel has the Magnification ratio set to 50%, but the comp resolution is set to Full. Resolution should be set to Auto, so only the pixels in the Comp panel will need to be rendered. Just changing the Comp Resolution setting to Auto (half) should give you a ram preview that renders faster plays back as much as four times as long.
It looks like you are expecting After Effects to behave like an NLE. AE is not a video editor, and the length of a ram preview depends on available system resources. If you have the Info panel open, you can see the playback frame rate. You can use the Preview panel to skip a frame, so you get longer preview times.
I don't see anything I would not expect in your project, especially if you have a system that just meets the Minimum System Requirements for AE.