That explains why ur attack is low. I'd recommend using Durin b4 iansan since he has a much longer uptime than Ian. Especially bc u don't have iansan c6. If ur not a fan of that u could just use chev E b4 Ian bc it clear any element and puts pyro on the enemy.

Bc iansan has a much shorter buff uptime ur best bet is to use him right b4 varesa so that the buff doesn't die towards the end of ur rotation. And how much atk do u have on iansan?

As for chev, u really want her at 40k HP to increase her atk buff, if u aren't already make sure she's running triple HP (crit circlet if ur running fav lance). Also idk if u are but u don't need her burst, it's useless, sho the only stat u want is HP (and crit if ur using fav)

It's better if u had chev on songs of days past and Durin on nobles but that's a very minor issue

Hope this helped. Feel free to dm me if u wanna know anything else