The last part of song is Enna mix another 山下達郎 's classic famous song "Plastic love" as a little surprise. Elira Pendora from Niji-EN have a Plastic Love cover for her 3D reveal stream, you could check it out too !☺
I love your analysis so much!! I would recommend the original song "Rose me" from Rosemi, from Obsydia. It's less known than others but it sounds very good! Not speaking of vtubers I reccomend to listen to 2 j-pop singers, Mafumafu and Ado. From Mafumafu "Hunger" and "Black Christmas" with Soraru, while for Ado "Ussewa" and the cover of "God-ish". I LOVE THEIR VOCALS AND I HOPE YOU CAN ENJOY THEM TOO!!!
Great reaction and analysis! Enna has such an amazing voice. If I may make a suggestion, I'd be interested in seeing you react to a vtuber named Omaru Polka from hololive. My personal favorite songs from her are her cover of Chimera, and her original songs Persona and Hologram Circus.