Video guide: https://youtu.be/pgIEJhkT-io
Finally got around to doing an Advance Quest guide. These are long form quests which require Advance Capsules to access. You'll first get access to these at Level 40 from Cofy, so be sure to check in with her when these become available.
What makes Advance Quests so good for EXP, is that there's a big chance of having PSE Bursts and Cross Bursts occur multiple times during the course of a run. Which means infinite spawns of enemies until the time runs out.
It will cost you at least 1 Advance Capsule to access the Very Hard runs and 10 to access Super Hard. Be sure to check the capsule type required when accessing a mission, as each will require a specific lettered Capsule.
If you run a quest that needs Advance Capsule A's, then you'll have B's drop in that quest and so on, until you run one that requires a C quest, which will drop A's. Super hard is the same, but replace ABC with DEF. To get the Super Hard Advance Capsule DEFs, head to Astracite Exchanger Rheinbraugher's shop on the 2nd floor left side of the Shopping Plaza. The exchange rate is 10 ABC capsules for 1 DEF capsule.
You can either run quests to increase the threat level or pay capsules to increase the threat level up to 50. At level 50, it will be at the highest difficulty, which isn't that difficult. You'll want to run +50s from level 50 to maximize your EXP and be sure to run with a full party, Photon Booster and EXP boosts to ensure you get the most EXP out of each run.
When you're in an Advance Quest, be sure to kill every monster and check every dead end as enemies will not respawn. Eventually, you'll finish the mission boss and get your threat level ranked up. Photon Boosters also drop regularly here, along with 11*+ equipment. You can trade in Photon Boosters on level 2 of the Shopping Plaza, left side.
Doing this is a good way to fill time while waiting for Urgent Quests. Combining both and you'll be Level 75 in no time!