I read this question two different ways, so I'll answer both versions: in terms of the ending (song), I'll give it a 10 because it really is quite the vibe-able song (I think overall its melody is a little less memorable than some of my top Atelier EDs, and melody memorability is a huge standard by how I rate my music, but we're asking about vibing and I think it fits the mood perfectly).

Regarding the ending (story), I'll give it an 8 (-2 for being a bit too obvious it's an in medias res story, even if there's not much they can do about it from premise alone, but everything else was excellent and feelsy). I can't say too much without spoiling, but also, isn't Ramizel just the epitome of the millennial fantasy? Imagine being in your twenties and absolutely sure you're not going to make anything out of your life and then someone from the future comes to tell you eventually you'll be an amazing accomplished person who's an inspiration to everyone around you. Like, man.