Just like any other Gacha game, Zenless Zone Zero follows the formula of creating characters powers and abilities based on their rank. If a character belongs to the A-Rank in ZZZ, theyre not supposed to compete against S-Rank characters that have more value and can offer more. This makes sense since A-Rank Agents are easier to get compared to their 5-Star counterparts, which requires far more summons on their respective banners.