This is top quality advice from one of the best movie journalists in the US.
Game of Thrones Season 8 Episode 3 was commended enormously as one of the best episodes the classic movie has produced. But one major downside on the lips of viewers across the world is that the scenes were too dark for anyone to see exactly what was happening. The Battle of Winterfell which took 55 nights to shoot has been described as the most fantastic battle scene throughout the movie so far. But viewers hardly saw what transpired as clearly as they would have loved to. They complained that the images where too dark and muddy for anyone to enjoy what they were watching.

According to Chris Welch while reviewing this episode, “The Battle of Winterfell, playing out in the season 8 episode “The Long Night,” took an arduous 55 nights to shoot, and was the largest-scale battle sequence in Thrones history. It was meant to be a final-season flex of epic proportions.”

Welch in his article further explains that Miguel Sapochnik’s close-up directing choices and the battle’s nighttime setting were a perfect combination to expose the weaknesses of the streaming world we live in today.
There was a barrage of complains by many fans about constant pixelation and an extreme difficulty following what was transpiring on-screen.

The main option for getting the pictures improved is compression. Welch has this to say about compression and improved quality of Game of Thrones season 8 episode 3: “By the time Game of Thrones reaches your TV or mobile device each Sunday night, it has been thoroughly compressed — both by HBO and by your cable / satellite / streaming provider of choice. This is a necessity to make the show accessible to a wide range of people with different internet connection speeds. Compression is also applied on the fly for everyone tuning in over cable, where the downsides can be more severe and noticeable.” So compression even makes the dark picture look great.
How to fix your TV settings to re-watch Game of Thrones Season 8 Episode 3

Here are some ways you can try addressing the problem:

Find the best-quality stream
Video bandwidth is king when finding the best stream or download of a TV show. You want the show delivered to your device at the highest-possible quality. No cable or streaming box will be able to fix up a noisy, pixelated video stream if that’s the source material it’s given from the start.
Read interesting details here:
https://massmediang.com/how-to-fix-your-tv-settings-to-rewatch-game-of-thrones-season-8-episode-3/