I agree.
I read a great article recently that basically said the problem we fans are all noticing, but having a hard time putting into words is the switch by the writers from a Sociological point if few (aka main characters die off but the story keeps going, there are no real evil people or pure good people, just people and how the decisions of the world around them force people to change what they do etc) to a physiological point of view, which is what everyone is used to in movies and TV (characters point of view is why things happen, you need fan favorites to survive since you rely on them to tel your story to the audience etc)
Basically, once these two took over and had no source material, just an outline on the basics on how it would end, they reverted to what they know and crash landed this baby into the swamp.
I’m most certain that GRRM told them that Dany would go all mad king....but left to their own devices, they didn’t know how to get there from the sociological point of view that the books and early seasons of the show were based on.
Basically, unless GRRM wrote it, it was almost always going to end like this regardless of the Hollywood writers they threw at it.