>>529090684
Don't be discouraged by the amount of clothes you have, you'll quickly get more pieces and sketches as you progress and explore. Events are great for free clothes, pay attention to the rewards of activities.
As for the gacha aspect you can get a lot done for free, but getting pulls is a long term thing. Completing dailies is a consistent source of diamonds but you also get a lot from quests and minigames. Don't use your diamonds for permanent banner (blue crystal) pulls, since they are permanent you will naturally gather those crystals.
Banners come in 4 star and 5 (plus pity 4) star varieties. 5 star outfits have the best stats and effects but have more pieces and each piece takes at worst luck twice the pulls than a 4 star. My advice is to avoid 5 star outfits unless you are very sure and have 24000 diamonds to burn. You may also not roll for an entire outfit and just take little sips of each banner, you won't get something that matches and you will trigger completionists, but you have more pieces.
The Surprise-o-Matic in Florawish is a worse scam than any banner