Auto+ Priority
As you are rerunning the same team repeatedly, using Auto+ can make your life significantly easier. Consider if your characters have slow or less impactful moves, to remove them in the character's Equip menu. Auto+ has a priority for selecting which skill to use, ordered:
FR (if 100% FR Gauge) & FR Echo
BT+ Finisher
EX (if charged)
LD
S2
S1 (if S2 was previously used)
Sometimes removing FR or BT abilities can be very helpful for speeding up your run (depending on the unit and fight difficulty)!
Auto+ Farming is a quality of life and is not at all required! You can take your eyes off the game, and let your team finish basic quests Lv100 and below! This includes Summon Boards, Cycle Quests, and Artifact farming. You can turn on Auto+ by pausing a battle and choosing Auto+ in the top right, and then turning on Auto+ with the blue button at the bottom to the right of your character's HP/BRV amounts!
General setup is to use as many of these Auto+ Farmers in a team as possible, but MANY characters are not listed but perfectly useful, as long as they have AoE attacks. For harder quests closer to Lv100, try to include at least Tractor in your team. Auto+ Aura bots below are helpful for lowering turn counts by letting the farmer/tractor naturally deal more damage without using a turn.
Summon board farming is special, and has recommendations further below.
Literally any BT+ unit works for all summons except Shiva or Brothers cuz they're stinky.