I believe The Beatles: Rock Band came the closest to being perfect. Eveything about that game was just beautifully done and the only things missing was Pro Drums, an option for Keys, and a few more Beatle songs (Hey Jude, Strawberry Fields Forever, Yesterday etc. etc.)
It’s hard to define perfection but Return Of The Obra Dinn has very few flaws IMO. I can only complain about relatively minor UX problems. Everything else is incredible. I still think about the story years later and the music gets stuck in my head to this day. It is such a consummate achievement of game dev and its design achieves maximum results with the limited resources of a solo gamedev.