Alright guys I need some help. I've been playing since day 1, religiously doing 99% of all dailies and weeklies, and most events, (while skipping some story), I've never been one to go for META or min/max and stuff like that, so I've been taking my sweet time just hoarding and enjoying whatever. However last week I got really hooked into the story mode and wanna do campaign as far as I can.

I have never opened a single "core/exp" box, should I do that now as I hit the wall? I can't kill this boss, I know the team is horrible I just put the hightest CP's to skip the campaigns with no story.

1) Should I just full send my shit and use all my boxes? Or use just a bit till I get over this wall.
2) In these cases, is CP better or is the team better? Or both?
3) Any suggestions in general appreciated.

My outpost is level 168, I've barely done hard mode campaign.
I have all the nikkes except the ones pictured in pic related.