Well keep in mind the one great aspect to StE, is if you run a team without red and she has a max level orb change, you can run high damage combo helpers and still heal yourself consistently because during the 5 charge turns you don't really focus on reds as they just clear the board, 5 turns pass, throw in hearts, it will be enough to combo you to full and then just match whenever you need rip bad boards etc. It really does let you clear some semi difficult stuff substantially faster than driving an auto healer. As someone who fucking hates grinding for days on a boss its always nice once I figure the threshold and can double adk with siren inside, or adk/odin leaders with siren in the team or issis/odin with siren on the board. She's easily the best non leader healer with a maxed out skill - assuming you are not running a full on red team as her orb swap never impacts your dps negatively and cancels out a color that yields nothing but combos.
tldr: You can Ama odin to eventual victory, you can ADKx2 or any other combo leaders to farm speed, and you can Odin or Resist + Combo leader with siren in the team to speed up that middle difficulty.