"The Past is written. The ink is dry."

[Angel Eyes]

For Game of Thrones, if the past is unchangeable, is the present and future so? Is this intended as a nihilistic message?

I'm referring specifically to Season 8's last two episodes in regards to Daenerys' actions. Did Bran know that Sansa would tell Tyrion, and Tyrion would tell Varys? Did he know Daenerys would go mad? If so, did he know and allow it to happen? Did he intentionally allow these things to happen so he could become king?

[Mystical]

The ink is not dry. Bran proved that twice. The most memorable being his warging of Willas in the past which caused him to become Hodor. When he called out to young Ned and Ned turned around, that was also him having influence over the past. The then 3ER looked really worried. I always saw his 'ink is dry' explanation as an excuse to deter Bran from trying anything in the past (Hodor being the exception since that was neccesary for Bran to get north and later escape the cave) because Bran still had agency back then.

The ink is also not dry on the future, otherwise 3ER wouldn't have interfered to steer things in a certain direction. If everything was set in stone, all 3ER had to was sit back and watch things unfold. There was no need to determine when to tell Jon of his parentage because we can be sure that Sam eventually would have told Jon. But the 3ER clearly needed it to happen at a specific point, hence he interfered.

There is really no answer to most questions regarding the mythos because D&D flat out refused to deal with the supernatural, in this case the Old Gods/Children/3ER. In order to know the answer we would have to know the purpose of the 3ER in the bigger picture. Agent of the Old Gods? The Children? Neutral force (which is extremely unlikely)? There is a purpose to the 3ER becoming King, the question is what that purpose is. And we have no answer for that.

[Narsil4]

Bran was possibly being shown memories contained within the Trees.  

Rather than changing the past, he could have just been distorting the memory of it.  

So he may have not been what caused Hodor's state, but was caught up in the memory of it and experienced it as if he was the one causing it.  When it may have been Bloodraven or someone else.