By default, iOS automatically deletes update files after they have been installed. If an update file has not been removed, you will need to delete it manually. In some cases, an incomplete iOS installation may be the reason the update file remains. To resolve this, you can attempt to finish the update by navigating to Settings > General > Software Updateand selecting Install Update if it’s available.
Deleting the iOS update file from your device storage doesn’t cause any significant issues (See the Pic 1). When you decide to update your iOS later, the system will simply download the necessary update again and proceed with the installation. Essentially, you won’t lose any important data or functionality by deleting the update file.

This is what I have on iOS 18.2.1 on iPhone 12 Pro
