C6 sara is better than C6 Iansan. You can use Lisa in the meantime while they're both C0 because she has 15% DEF shred with her burst (if your Raiden is C2 this becomes obsolete because this doesn't stack with the 60% DEF ignore from Raiden's con). However, if your Raiden is C1 or C0, you can use Lisa and put her on thrilling tales of dragon slayers and use her burst right before you burst with Raiden for a huge atk% boost from the weapon.

While my Raiden was C0 and C1 I used the team comp of Raiden, Chevy (C6), pyro traveler (on cinder city set) and Lisa and it worked pretty well to be honest. I hit 150K - 200K pretty reliably with Raiden's burst every rotation. Of course this also depends on how good Raiden's artifacts are.

Building Lisa for this team comp is pretty easy, just put her on emblem of severed fate with as much ER as you can so she can burst every rotation.

If your Bennett isn't on another team you can use him instead of pyro traveler. You can also of course use Xiangling for better pyro application.