Watching HD movies is what many people usually do for fun. However, in a bid to cope with large amount of visits resulted from COVID-19 stay-at-home order, and Netflix degrades videos and movies quality from high definition to standard quality. This move aims to protect their servers from crash. That being said, it can't stop network jam or movie freezing issues during online video playback.
In such case, the better way to go is to download HD movies for offline smooth enjoyment.