tires can be the same height with an 18" rim or 20" rim, so 20" can have 2" fewer sidewall. Tires come in many sizes so my statement is just general for easy numbers.
I wonder they are putting different cameras in the low lower trims than the higher trims(maybe leftover parts) I see a YT reviewer that tested an XLT and then a Lariat mentioned a night and day difference in backup cameras. Wonder that the part numbers are for the two different trims?