Timber made a video on how to skip GSI but it takes a long time and requires a second file. Hope the community finds a way to optimize that strat to be speedrun viable.
I looked at the botw speedrun history and it seems that at the point in time we are now for totk when regarding botw, the speedruns were about the same time. Sure, the scene wasn't as competitive, but if botw speedrunners were able to cut that time in half, I remain hopeful about totk speedruns.