https://wccftech.com/apple-issues-mac-ios-device-syncing-updates-through-software-update/

Apple had seen fit to issue a standalone update for macOS users called "Device Support Update". The purpose of the update was to ensure the proper restarting and updating of iOS and iPadOS devices using a Mac. Moreover, no other details were provided regarding the update. In addition, it was not clearly stated that the updated added support for recently released devices. Scroll down to read more details on the subject.

The new "Device Support Update" was the first of its kind to reach macOS users through System Preferences > Software Update. Usually, upon connecting the iPhone or iPod to a Mac, a dialogue box appears from the MobileDeviceChecker app that says "A software update is required to connect" to your iOS device. What this means is that a device has been updated independently with a newer version of iOS or iPadOS which is not recognizable by the Mac. Henceforth, your Mac would require a Device Support Update to proceed with the syncing.