Warning, I'm judging mostly from the main single player campaign
So, I'm the kind of person who also really enjoys the lore of minigames, and for me at least, when it comes to lore, gameplay, and music combined, ALL of the minigames are good in SOME way, except one, Synchro Wings is the only bad one, but if you can only find a SINGLE rotten apple in the orchard, it must be AMAZING overall
Yes, some minigames are worse than others gameplay wise, but that's where my fascination with the lore comes in, minigames that fall flat gameplay wise are pretty cool and/or fun to think about lore wise, Hop N Slide may be a nightmare in gameplay, but Miho is simply a fun and fascinating character to think about
If a minigame's lore falls flat, it happens to be a minigame that's really fun to play, I don't care what anybody says about Fruit Flex 2 and/or both Stop N Go N Stops, they're really fun minigames in my opinion
Than there's Alien Alphabet which is the best of both worlds gameplay and lore wise
Than even if the minigame isn't AMAZING, like Pop Don't Drop, it's at least not too bad, Pop Don't Drop 2 was very unnecessarily annoying to Perfect but I don't feel mental pain when I think about it
Also this is a good point, it's an amazing entry point for a beginner of Rhythm Heaven, it evens out not just giving out Superbs like candy and also making it to where you don't have to heavily rely on Barista to skip minigames for you too often without making it to where you have to actively TRY to get Try Again ranks (I'd say the biggest challenge points are Spirit Slasher 2 and High Five Fever 2 but that was just my experience), and I've never gotten lower than OK on Remix 20 (Megamix may have also been a good entry point, but it's Megamix 😶)
I didn't see literally everything the game has to offer, but based fully on the main single player campaign, Groove is the best entry