Why won’t this app fit to my iPhone XR – 30 Day - Ab Challenge Review

I began using this app when I still had an iPhone 7 and fit it perfectly I could see everything, I could tap on everything. I recently upgraded to an XR now everything is zoomed in and I can’t tap on things on the far left or the far right. I tried deleting it and downloading it back but that didn’t help.
Review by 06Alyiah on 30 Day - Ab Challenge.