It takes like two seconds to scan on the app when you check in, once you do this it won’t ask again, you can also scan at an airport kiosk next time you travel internationally. As others have said it won’t solve the issue for the long term to go to an agent, you need to either scan it on the app or at an airport kiosk,

I would say that the american app works better for scanning but with a little effort the delta app will work,

once you have your passport scanned it will show as verified for your next trip, I would say that like every two years I need to rescan mine but once again this can be done quickly at home