Banyue Dialyn Lucia

After his signature, Wrathful Vajra, his next best option is either other S rank rupture engine (Qingming Birdcage) or Grill O'Wisp. Though Grill O Wisp will not have its CR effect active, so with it, Banyue crit value will be a bit rough and require more crit substats to perform well.

Fire damage D5 is the best for Banyue in comparision to HP D5.

As near to 100% CR. High energy build is best for the stun rotation planning. the more of Dialyn EX inflicted, the more daze she inflict and the better her buff uptime is. Her EX Special Attack: Paper! deals the most daze.

W-Engine alternatives are either Hellfire Gears or Steam Oven, but because of Dialyn attribute disadvantage here, getting 4 full stun rotation without her signature or high refinement Hellfire gears might be hard / not possible.

W-Engine alternative is Unfettered Game Ball for ether weak enemy which works very well, or Weeping Cradle that has at best 50% uptime on its buff uptime on stun and need to ramp up first. On weeping cradle, using Lucia EX mid stun and tuning the timing of her aftershock mid Banyue ultimate animation would be the best to get its full use, but its still not going to fully buff Banyue damage.

2400 HP for buffing requirement, without her signature might be hard to achieve, then 2300 is good enough.

ER or impact disc 6 is also an option, but not necessary.