Sorry - don't have a definitive answer. Try different frame and bitrates. Results varied in tests here.
Jerkiness was also evident on some of your clips rendered by another editor.
On your next project you might test various shooting/recording options, if available. A lower resolution perhaps, to lighten the load at minimal quality sacrifice.
That's not meant to be an excuse. Because a camera can do 4K doesn't mean that's best. Then again, only you can decide, and UHD is becoming common and should be able to be handled reasonably. Proxies can help.
The timing issue in your other thread is being pursued.