My team composition as below.
Everybody was mentioning about aeqour, however I just joined so totally no clue that water is so strong for clearing story actually.
#Anybody can help on team building ? TT currently was stuck at Arc1 7-12
rancid oasis
pearl anchor
Afaik, people tend to recommend aequor because tentacle damage and shielding is pretty strong early on and, historically, the aequor banner had a pretty low amount of "bad" awakeners. Issue is, though, that tentacles fall off as you progress since it doesn't scale super well (unless you are running divine aequor, but you do not have any awakeners with it so don't worry about it). Also, nowadays, (almost) all standard awakeners have their niche and all realms have a good balance going on.
My advice would be to check Cheri's guide (particularly, the section "What Banner Should I Pull?") when it comes to pulling advice. As for arc7, you should have no issues running Saya. I'm thinking something like Saya/Thais/Aigis/Clem (Clem dps, try to get her to e2 in this case) or Saya/Thais/Clem/Jenkin (Jenkin dps). You could run GHelot/Thais/Aigis/flex (Clem, Celeste, Faint), but if you are already struggling, then lacking GHelot's enlightments is not helping.