Hello, so there many different quests you can do. The "max attacks" on Ep4 do have a good start for resetting like the first room at least if what you're looking for. Also give <https://www.pioneer2.net/community/threads/leveling-and-you.24960/> a look, did a quick write up on lvling to give you options.
New Mop-Up 3 or Towards the Future if you have someone to carry you through your current difficulty. It's usually pretty easy to find (or make) TTF parties for whatever difficulty you're on.