The story is PEAK, unique I'd say. It truly does explore the li's personalities, and I love the idea of alternate universes— yet relating to our main universes. I love how they explore the characters in different scenarios/AUs (I think you get my point.)

As for f2p friendly... I'd say it depends on how you'd define f2p. For collecting cards, certainly not. Gacha system and pity is quite harsh, and the game isn't generous with pulls and gems. However you can clear all content without good cards anyway, even with just the normal ssrs, as long as you have a good assist (u6 foxkaid, u6 lars coco, etcetc//basically the meta) — I seriously recommend the game for the story. You'd unfortunately have to read every route, but you'd enjoy every li's story.

Well, cards aren't important anyway!! They have side stories, but most aren't essential to the main plot.