They need to get bloody on with it and have the Targaryens fighting each other over the seven kingdoms, while the North and South struggle to survive in a jilted alliance against them while continuing to play the game to ensure their own victory. All this thrown up against an
actual white walker invasion for shits sake lol.
Spoiler
And in the end, Jon and Arya need to kill them all, claim Dany and the Dragons, and Arya marries Tyrion who is crowned King of the South while Jon and Dany rebuild Winterfell at the wall and rule the North. Sansa can just hang out with Littlefinger and stare out the moon door for the rest of her life.
Martin has plenty of set-up, he just needs to follow through. Stalling in the second act is both common and forgivable, especially given the bloated nature of his storytelling lol. Just don't die you bastard!