@Jonathan212: Is the issue occurring with all content viewed on Prime Video, or just certain videos? If you pause the video for a few seconds, then resume playback, does the issue persist? If you're streaming the content, have you tried accessing the site via Wi-Fi and Mobile Data respectively to see if you notice an improvement?
In the meantime, please take a look at the link below to find tips on reducing audio lag while wearing the Galaxy Buds range.
It sometimes happens in the Samsung Gallery.