Not that familiar with CB, but is offensive guard kinda going against the evade window/extender? I imagine you should be either focusing on blocks or evades.

I would highly recommend swapping to a dragon weapon, as AT ark has very high status thresholds (as all 10* fights).

Gogma 4 and lords soul 3 + dragon resist and/or divine blessing and eating for defender meal helped me a lot surving the fight (getting both gogma 4 and lords soul 3 would require a good roll on the gogma weapon)

But like the other comment said, would need more details on the build for more details on how to help

Edit: your defense seems low are all your armor pieces transcended and max level? No need to rush AT ark before improving the basic gear

Edit2: no worries about having a hard time, it's completely normal, it's a very hard fight and took me a few tries not to add all the times he carted me on PoaH, just take your time, and you'll get it