The tires are still considered 17"s. unless you really want to try to force it on an 18" rim. I saw a 15" tire on a 16" rim once. There was a lot of head-scratching but considering who did it no one was really surprised.
I haven't seen it done recently but 15 years ago you selected a different tire size with the scan tool. Sometimes you could get close but not dead on. I remember a tech complaining that the selections were limited, I'm sure it's much better now.
https://www.f150gen14.com/forum/threads/2021-f-150-side-view-vs-current-f-150.83/
Actually, the actual 2021 door handles look slightly longer. The easiest way to id the 2021 is the fuel door. 2021 looks like the S.Duty, not round.
https://www.f150gen14.com/forum/threads/ford-workers-refuse-to-work-and-shut-down-the-line-at-dearborn-f-150-plant.88/
A video taken by an autoworker and obtained exclusively by Labor Notes shows a rowdy and chaotic scene inside Ford’s Dearborn, Michigan Truck Plant on Wednesday as workers refused to work after a co-worker tested positive for COVID-19.