That's a cool theory. Not sure it's true, but she's betraying Kaido.
nah she's not betraying Kaido
people don't understand how bad writing that would be
not in the sense that it won't make sense , but it would be very cheap plot development and getting the protagonist out of a major threat without them doing anything to deserve it
Oda don't get to build up Kaido arcs for years then suddenly there's an alliance with BM that will lead to his downfall, so Kaido threat basically solved itself
the reason for Kaido and BM alliance is to establish them as major threats to the whole world , meaning their plan will succeed
remember the information of another Ancient Weapon is here in Wano, it's in the form of Karibou
I say Kaido get Shirahoshi and BM get Uranus