Merch isn’t different from the land however, which is supposed to be canon to between 8 & 9. How would they have stuff from Episode 9 if they are being strictly canonical to the middle period? Obviously they aren’t. I’m more than fine if Batuu loses its timeline and we can have any SW characters within the land (within reason).
And yes, even if the ride narrative makes sense after TLJ, like I said, I and all SW fans will know what happens in TROS, so many elements of the ride are now awkward. It’s not like they explicitly state to you at any time while in the land when the land takes place.
For example, when Kylo comes and walks “menacingly” through Black Spire, that no longer works because we know his fate. People will probably want to see something else, but it won’t be able to happen either due to how the film ends.
It just makes things a little messy since only people on message boards will know the timeline.