Swapout Luluca for Violet.
That being said, not much can be done without knowing gears/stats.
The problem is, A.Coli is good at defense in guild war system, but not in Arena no matter how fast you are she will randomly attack once and people mostly don't care who would she attack if she cannot kill them > useless defense move.
If you put A.Coli in your def team you must be confident she can one-shot anyone that she target first. You can't expect you win many times with defense team unless you have gears at g.o.d tier like those who are on Legendary rank.
Defense AI works stupid and your team formation is easy to target at.
Anyone with high speed Dizzy can literally beat your team. If your A.Coli didn't stun Dizzy at first turn (in case she's outspeed Dizzy). And if Dizzy was outspeed her > You are doomed.
SSbellona > missed
Luluca > Missed
Deals with the 3 of those of your DPS and they then can slowly digest your Krau. > Mission accomplished.
I'm challenger 2 and lost 84 times won 11 all to cleave and I noticed 1 dark Corvus team people complained about stall and Smilegate adjusted that just the game without insane gear right now but power creep and balance updates will probably swing it the other way soonish right now u kinda have to spend skystones for flags to climb
Try adding a cleanser at some point. Also you're vulnerable against Earth heavy attack teams.
They will always target your krau 1st, the rest of your team are easy kill. Make more 6* unit.
M.Coli is fast but easy to use element bait on her! and if enemy can cut in after M.Coli, you done for
Get 4 good healer x 60, and I hate that team ^^b always skip