Dunno what kind of lies you are spouting but The Last was in production since 2012, which Masashi Kishimoto helped cultivated the story, made them rewrite the script 3 times, and then added his own elements from his marriage into the story.
Kishimoto began to write the Boruto: Naruto the Movie script in 2014, which he announced earlier plans in Jump Festa (2014). Which is an entire movie about Naruto's family, with Bolt as the MC, and with Sasuke joining him as supporting character.
Kishimoto wrote the Gaiden after he wrote the script for the Boruo movie, in fact, I don't know what kind of person thinks a one shot-Volume would take a year to create in the first place. It's quite baffling.
Anyway like you were saying, IT IS pretty obvious which one he holds in more regard since he thought of them first. But hey, it didn't come out of my mouth. Just using your logic.