Tier III of grand inquisitor is not possible

I have relic 5 inquisitors, have tried every lead. The first round with grand inquisitor is annoying but easy compared to the second. In the second round you fight kanan, who heals 10% health every time he gets a debuff, and the inquisitor team does debuffs for every attack including basic. Now you are probably thinking, just do armor shred with eighth brother right? Wrong. I’ve gotten to the point where I spent an hour and got more than 30 armor shred on kanan, and if I set it up justttt righttt then I can get him to half health. (Again I have tried every lead even used marrok). Now, when I get a great circle of turns and get him (miraculously) to half health, he happens to have an ability that heals him and gives him a ton of bonus protection. And the only attacks that will get rid of that, deal debuffs. Even if I basic all of it down, he still heals all the way to full. I have (regrettably and embarrassingly) spent more than an hour on this single round. CG, this is one of the first journey characters the new players will be getting ahold of due to the light speed tokens. Please fix this, I know you probably only have a skeleton crew for this game but this is actually driving me to insanity.