There is an issue in Amazon prime video, Quality is reduced to SD resolution btw previously it was 720p and 1080p. I don't know why this happened but it was after the June security patch update. My mobile Samsung galaxy A50s.
Dear Samsung Member,
Greetings from Samsung Customer Support!
Kindly be informed Amazon prime is a 3rd party application which is not from Samsung. As we are trained to handle Samsung software and hardware related troubleshooting, we advise you to contact to the respective application software support. You can reach to the app developer through email channel go to: Play store > select more option> select installed app> click on read more.
Thank you for writing to Samsung.
Samsung Customer Support