Tyr's plan for peace failed though between the aesir and vaenir. He knew that if left alone the gods would incur Ragnarok anyways. So my guess is his plan was to take Kratos from his world to his own so Kratos would kill the gods before that could happen. Even though Kratos pretty much destroyed his world he left humanity with a sliver of chance free from the tyranny of the gods and to forge their own path.
We know that Kratos is still the same Kratos from GoW3 due to the scar from Athena's blade so someone had to drag him from there and heal him.
Killing Baldur was in the plans because if left alone he would have eventually killed Freya which would have brought Ragnarok anyways.
I know this sounds crazy but I think Baldur won’t kill his mother Freya if Kratos didn’t interfere ..
and going to Tyr I think he has no intention to awake Kratos past cuz that will make it worse on this world and on Kratos himself even if that means killing gods and saving this world .. do not forget the son maybe that’s why one of the paths Atreus will kill his father regarding that vision of tyr’s
And to be more precise.. mimir is the key to everything after the disappearance of Tyr , you know that the Giants put bifrost crystals
In the eyes of whom trusting .. right ?
That would be Tyr and Mimir .. and there is something weird about mimir when he asked about some mysteries regarding Atreus or Faye , he will dodge that question with another story to prevent the collapsing of Faye’s vision to The father and son ( my theory is Not involving Tyr as the main but Faye and mimir also has a role to play .. big one )
And to just correct something you said .. the world serpent does fight Thor in Ragnarok .. that’s why future did happened