Review based on my own opinion from playing since global launch (October 2023) (Currently on version 1.9)

Gonna compare this game to Hoyo games a lot, since their games kind of set the standard for most gachas.
In this game the "premium" characters are the 6 star ones, where the 5 stars are the "standard" (which you can get easily)
There are 2,3 and 4 stars, but these characters you'd mostly use starting up and never use them again anymore, with some exceptions.

Pros:
-Great story with interesting themes.
-Phenomenal art from start to finish, and the game really nails the immersion on the VN-like story telling, also, you can unlock beautifully done skins from characters from just leveling them.
-Some really different designs compared to the standard gacha, like, there's a literal dog as a 6 star character, and a "flying cape" with a sword.
-No Weapon banner, you can just get them all for free (great, since you can focus on getting
the characters, which IMO is way more fun than spending on weapons.)
-Most of the characters get in the standard banner some months after they are released, in 1 year they got 12 "6 stars" in the standard banners. (19 were released.) this is great since there's stil a 50/50 here and you'll probably always get a new character from losing it.
-90 froms daily currency(compared to hoyo's standard 60), 100 from weeklis,10 basically free pulls per month, and atleast 10 from daily login in new patches
-1.5% premium character drop chance compared to Hoyo standard that are 0.6%.
-60 soft pity and 70 hard pity, compared to hoyo's standard that are 80 soft pity and 90 hard pity.
-They are planning on buffing old standard banner characters, which is something you normally don't see on gachas.
-Great dub, there are a lot of different beautifully done accents in the game.
-You can choose separately if you want a character dub to be Japanese, Chinese, Korean or English. (Which is something great and i hope more games follow this)

Cons:
-The story is great, yes, but it takes time to get to that point, at the beginning there's too much thrown at you and it gets too confusing, and not too much is concretely explained until later.
-There's some missing attack effects on the global version (like Lilya extra attack missiles)
-Global version is way more predatory with its banners, putting meta characters in "bait banners" a lot
-They are starting to launch more and more characters that are limited and won't get in the standard banners, currently there's 1 per 3 patches.

Great game. If you are reluctant in trying this from it being a gacha, cause you don't like how gameplay is basically tied to spending and RNG, you can give this game a shot because it's actually pretty fair and i've been playing since october 2023 and i have 21 "6 Star" characters in my account from 30 currently avaiable, (i mostly bought the "monthly subscription" and bought some 10$ packs and that's it) i could've gotten more, but i did breaks from time to time from the lack of content i had from playing too much on a specific patch.