There is a playback quality setting in Netflix website under your account settings. You need to choose High quality and have UHD plan if you want to watch HD content on your tablet. But my Tab S6 won't go past 720p in Netflix, no matter what settings I use, even if the device is on Netflix's HDR compatible list.
Please tell which kind of results do you get with these settings. You can test the quality with searching for test patterns in Netflix.
