Tsunade can activate the Byakugou without hand seals.He can make another ritual, however if he was to obtain blood before byakugo was active and then activate the ritual she'd die right? ...But that requires no intel,
Anyways again im not seeing how punching the ground is as effective as everyone thinks, He simply needs to jump backwards to avoid it, and while hes jumping he can use the scythe in mid-air to attack tsunade, which yes she may tank but its damage none the less ,
So then how exactly do you counter Byakugo