You did a good job considering you were only using base EGOs.
One tidbit that might help: When you're choosing attacks, the last attack you assign will override the previous attacks. So if you put multiple sinners on the same speed dice, then make sure to re-assign the one with the highest chance of winning last so that's the one that ends up clashing.
Thanks I'm still new to the mechanics when I see 'Dominating' or 'Favored' I just roll with it 😂
This boss is somewhat fun ngl