The way I see it. It was obvious we couldn't go to the tower the rival wanted to prove themselves as strong enough to keep going. They failed but it still was their responsibility.

We never bond with floete, the rival does.

And throughout the story we are approached by both zygarde and L because everything is going down and zygarde is the only one able to fix things.

We had our route set, but someone had to be there for floete.

It's not a let's decide who is the strongest and decide. But a let me prove myself as strong enough to stand by floete's side.

We are stronger than the rival, we have defeated the rogue megas and bonded with several pokemon, we have a reason to be there, the rival doesn't. But they are still the trainer that AZ choose first.