It's easily Outer Wilds for me. While it's a game I played for the first time just three months ago, it's one of the best games I've ever played, and one of the thoughts I had after finishing it is that I wish I could experience it for the very first time again in the future. Part of what made the game so phenomenal for me was being able to go into it blind and be filled with a sense of wonder, a sense of discovery, a sense of accomplishment, wanting to keep playing more and more so I could explore the entirety of the world and unravel all the mysteries the game had to offer and figure out how to reach the end of the game. It captured feelings I haven't felt when playing a video game in a very long time, and it does honestly make me sad that I know I'll remember too much of the game in the future to be able to have those same feelings again when replaying it, so that's what makes it the perfect answer to this question for me.
Honorable mentions would go to some games I've played numerous times over the years, just because it'd be fun to get a chance to play them all over again for the first time: Legend of Zelda: Majora's Mask; Skies of Arcadia: Legends; Metroid Prime; Pikmin.
Probably actually animal crossing because I’ve been playing for around 4 years now and would love to restart and experience the joy of playing it for the first time again!
I would have to go old school for this one. One of my all time favorite games is from the PlayStation 2 and I still play it today but I would love to be able to experience this game again.
What is this game you ask…well it is DARK CLOUD.
I know someone is gonna mock me for this choice but I absolutely love that game.
100% Curious Village. It's my favourite game, both in the selection I've played from the professor layton franchise and overall, and I enjoyed it so much when I played it first (which was actually only in September). My playtime of Curious Village is under 10 hours spread out over about a week or two (thankfully spread out over those weeks instead of binged in a few days). 10/10 would sell all I own to experience the storyline and gameplay for the first time again
I can think of a couple of candidates: Animal Crossing (GCN) or Pokemon Red/Blue/Yellow.
Now, experiencing them the way I would want to would be not having experienced any title after them, because like, R/B/Y especially, are very dated games nowadays. It just wouldn't be the same in today's world.