You're not raising all your heroes, are you?

It's best to prioritize and focus on developing one main damage dealer first. Spreading your resources too thin by leveling up all your heroes might lead to a shortage of materials, so decide on your core 5-member party and invest heavily in them. Especially since clearing stages as much as possible boosts the efficiency of offline idle rewards, it's crucial to keep progressing through the main stages until you hit a wall. It's more stable to build a party with a mix of roles like tanks, healers, support, and debuffers, rather than just filling it with damage dealers. For auto-battles, a composition that can endure and deal damage over time might be more advantageous than one that focuses solely on burst damage. Instead of spending too much time on rerolling, it's better to leverage early events and rewards to quickly assemble your main party.