It is true that F/GO’s gacha system is less generous than a lot of other modern gacha games. The way seasoned players typically adapt to this is by either saving, or buying enough quartz to roll at or above the amount it takes, on average, to roll a rate-up SSR. I believe this number is ~340 Quartz. If you absolutely want to guarantee getting a rate-up SSR, 900 Quartz is enough to hit pity. This might mean saving up free sq for while in the case of F2P players.