hi bro, some users did report green screen or white screen of death problem after updating to iOS 16.1 and iOS 16.2. So far I havent read any issue with iOS 16.3. still If you are updating and facing any problem like that, you have to talk to apple support and visit apple service center to get the device replaced.
I think in Sri Lanka, only at colombo you can find apple service center.
So if its reachable to you in case of any such green screen incident, then you may proceed with the update. else stay for some more time and then you may consider updating.