Yup ok then it's my recommendation. It's absolutely great and requires no prior knowledge of the property it is a fangame of to enjoy. I was just erring on the side of caution because it's explicitly designed to be like a regular Gacha with pulls and pity and banners etc but with in-game currency.

What about a game that has a Gacha, but purely using in-game currency. No real money purchases are even able to be made whatsoever, the game is completely free. I'm taking about Holocure, a hololive fan game, and it absolutely deserves to be on your list.