Hi bro, if current version is working perfect for your every day usage you may continue with same version. Also apple service centers are replacing displays if any green screen appears even if the warranty is over.
it may take 5+ years for app developers to stop support for older version of iOS.
Othertimes, if we are facing any crashes or issues, we have to update apps and iOS to check whether any server side changes by the apps causing such problems.
Also if one considers receiving security updates then we may keep the iOS version updated to latest version or not.
There are some users who still stay in older verison bro. so you can stay, and update within iOS 16 versions only to receive those security and bug fixes.