Hi bro, as its hardware defect we cannot be sure whether the issue will happen within warranty or outside warranty period. most users are experiencing it outside warranty period and some are within warranty period.
So far apple is providing free display replacement and confirmed by many of our users who experienced similar problem.
In srilanka if you have apple service center then you have to check with them whether they are providing replacement of display if such issues happen. Then you may buy it bro. after sales service is good in general. but this green screen or white screen problem is still bothering and a problem.
If budget allows you may consider iPhone 14 or 15 models, otherwise as last option go with 13 pro max if you are getting good deal and after confirmation with service center.
Once apple acknowledged and announces repair or replacement program officially, this wont be a problem at all. Else we have to depend on service center and apple support.
Pro or Pro max models always have superior display and camera bro. Here with iPhone 15 makes a standout with its USB C and Camera performance Wide Angle lens is better than 13 pro max. We may not see big difference while shooting photos and videos easily.
13 Pro Max is still good to consider bro. but my suggestion will go with 15 model if telephoto lens is not important to you. also telephoto zoom picture shots are limited with 3X optical zoom in 13 pro max model.
Gaming wise 13 Pro Max bigger display is an added advantage for comofortable holding and gameplay.
If battery not your concern, and you can charge in between a day when you have above average usage, then 15 is still a rockstar bro.