passcode not works after update iphone unavailable

Your data is not lost if you have a backup either on iCloud or iTunes.

If you see an iPhone or iPad unavailable message or "Security Lockout" screen

If you forgot your passcode, you can use your Apple ID and password to erase and reset your device without a computer.

Learn what to do if you see "[Device] unavailable" or "Security Lockout" on your iPhone or iPad.)

iPhone is disabled.

Following this process is the only way out if your iPhone is disabled. The steps given in this link will help you reset the passcode -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

Regarding your data…

1. If you have an iCloud or iTunes latest backup, then there is nothing to worry about. If not read more...
2. You have synced your data to iCloud, then what you will get back is what you have synced to iCloud and uploaded to iCloud Drive; the information that is synced and stored in iCloud are, Contacts, Calendars, Bookmarks, Mail, Notes, Voice Memos, shared photos, iCloud Photos*, Health data, call history, and files you store in iCloud Drive. (*-If you had turned on iCloud Photos, your content is automatically stored in iCloud.)
3. You have imported your Photos & Videos to Mac/PC then they are safely residing there on Mac/PC
4. You have uploaded some of it to Cloud Drives using the Files app (iCloud Drive, Google Drive, OneDrive, DropBox, Flickr, box, AmazonDrive, Adobe Creative Cloud etc). The data remains there.
5. If you have not backed up or do not have the latest backup, nor imported nor you have synced or uploaded your data to cloud drives prior to the situation that you are in, then I am sorry, all your data is lost.

Updating iOS on your iPhone should not change your personal details. iOS updates primarily focus on improving system performance, introducing new features, fixing bugs, and enhancing security. They are designed to preserve your personal data, settings, and information intact.

During an iOS update, your device's operating system is upgraded, but your personal data, such as contacts, photos, messages, and other information, should remain unchanged. However, it's always a good practice to perform a backup of your device before any major update to ensure that your data is safely stored.

It's important to note that while an iOS update itself should not alter personal details, it's possible that certain features or settings may be adjusted or improved with the update. In such cases, you may need to review and adjust specific settings to match your preferences after the update.

Always make sure to read and understand the update details provided by Apple before proceeding with an iOS update, and follow best practices such as backing up your device to minimize any potential risks or complications.