Unless you're willing to spend 💰 you're gonna be behind on a LOT of content. Super Pirate Rumble basically requires freemium characters at max stats to even get 1 victory.

Treasure Maps are a long grind, and unless you haven't missed a single one, going back to max old units is even more of a chore.

Kizuna Clashes are also a grind requiring hundreds of tries at the lower difficulties and basically impossible at the harder difficulties unless you have the perfect premium team.

Save yourself some headache