I lucked out and found what I wanted at the nearby Apple store. Canceled my iPhone Upgrade Program preorder and scheduled a pickup later this evening.
For anyone else in the same boat, the cancelation was a breeze. Took about 15 minutes for all the changes to churn through the system and my upgrade program eligibility was reset. This page is helpful for checking what's available around you. Just plug in your zip code, select the model/carrier of your choosing, and it'll tell you what's nearby. https://iphonechecker.herokuapp.com/promax13/unlocked/10111
Good luck!
For anyone else in the same boat, the cancelation was a breeze. Took about 15 minutes for all the changes to churn through the system and my upgrade program eligibility was reset. This page is helpful for checking what's available around you. Just plug in your zip code, select the model/carrier of your choosing, and it'll tell you what's nearby. https://iphonechecker.herokuapp.com/promax13/unlocked/10111
Good luck!