Even before Zeus and BM showed up, Nami’s lightning was hurting Ulti enough to make her faceplant, and Zeus makes her attacks like 10x stronger.
But that is not enough and it will take 5-6hits probably to hurt real damage Ulti.
As we see Ulti could easily react to Nami,she was fast enough even though she was 95% nerfed.
In the moment when Ulti see Nami power, she dodge it in her nerfed form and even with zeus they barely beat her.
As I said if zeus as powerup was enough, he would give Nami a proper great battle like enies lobby like, where she use tactics and zeus help to beat Ulti in a extrem diff battle but that wasn´t the case.
With using Bm, Oda legit show that Nami and Usopp where not strong enough, even with a powerup like zeus.
Nami and Zeus didn’t even use their ultimate technique against Ulti. Imagine if Nami and Zeus used the same attack they used in WCI against BM.
Ulti is not slow, with 100% she could easily dodge Nami, she already could do it in nerfed form.
Ofc Nami has great Ap, but she lacks in other things, like speed,reaction speed, haki, endurance,stamina.
Yes Nami is now stronger, but how Oda portrayal the fight, I don´t know but I can´t see Nami winning even with Zeus.
The only chance: Ulti recover to 50-75% and fight Nami+zeus and get defeated again but I doubt Oda doing this.
Pageone is the only one who I could see to stand up again since because of Usopp statement, but I doubt Ulti standing up anymore.
Probably Ulti and Pageone are down for the end of the arc....(with I hate it a lot).