Pre Ordering with Trade In

We currently have a 2 line plan under the Beyond Plan with both iPhone 15 Pro’s paid off. Anticipating the iPhone Duo just like everyone else but what can I do to have the best chance at pre ordering besides having luck? We’ve always traded phones in stone for credits/promos, but we want to be able to pre order immediately on 10/16 from the app or T Mobile website. Can you pre-order without purchasing the phone outright and have it delivered to the store to then deal with the deals/promos? Do I need to go on the account the day before to get the eligible promos available? Any help is appreciated so I can know what to expect without being hit with “pre order now for $2000.”