To be honest "movie" mode seems to dull the overall image, but my understanding is that it's a requirement for HDR.
If Samsung movie mode is the same as LG 'cinema' mode then that is their attempt at getting 'out of the box' settings that are as close as possible to calibrated picture settings.
I had my TV professionally calibrated and (laymans explanation coming up) the guy jacked the white levels down significantly - using the calibrated settings on windows makes a blank word page look almsot yellow
See if theres a pro calibrator near you, at least then you will know that the colours are how they are meant to look