Let's face facts, seasons 5 through 8 of GOT were not as good as 1 through 4.
The decline in quality is largely due to the show being forced to work without any original source material.
It's not entirely the show's fault, the book kept getting delayed and Martin tried to keep as much of it as secret as possible to prevent spoilers forcing more improvisation. Also adapting A Feast for Crows (often thought of as being the weakest book in the series) and A Dance with Dragons would haven been an unenviable task for anyone.
Unlike the first three books the story takes place across multiple locations that don't interconnect with one another and the timelines jump around a lot. There was also a huge amount of focus given to characters whose stories went nowhere (looking at you Sam!) whilst some key characters seemed largely forgotten like Sansa. That's before you meet all the new characters that keep being added throughout like Aegon Targaryen.
There was too much ground to cover and a lot of altering was required in order to fit in with the narrative the show had been telling.
Having said that, there was still fun to be had in the later episodes: some of the best action in the entire series, twists and revelations as well as key moments with devastating emotional impact.
Let's focus on the good times, and of course spoilers ahead, duh!