Why do iOS problems arise?

The fact that failures appear in the operating system is completely normal and can occur for various reasons. The first of these is that they are widespread failures that are affecting all users or a good part of them. These are caused by poor optimization by Apple and are usually more common in the first versions of a system (see iOS 15.0).

Other failures are those caused by the accumulation of junk files that are generally not the direct fault of the user. This is usually common when the device has not been restored for a long time and versions have been updated one on top of the other, appearing even more frequently when new iPhone models are configured with backup copies carried over from previous phones.

The latter are not usually excessively normal in any case, but they do occur. The good thing about them is that by completely restoring the device they are solved. However, those that originate from Apple's programming errors (or applications) usually have a less rapid solution and that is that in most cases you must wait for the company to release new versions of iOS to solve it.