Hey there alexfromsan dimas,
Thanks for contacting the Apple Support Communities today.
To get started, we do want to make you aware that this is expected behavior, and it would not be possible to restore a backup that was created on a later iOS version. This information can be found in this link here: How to uninstall iOS or iPadOS beta software - Apple Support
Note that backups created while using beta software might not be compatible with older versions of iOS or iPadOS. If you don't have an older backup that was made using the current version of iOS or iPadOS, you might not be able to restore your device with your most recent backup.
Do you by chance know if you have any other backups available? If unsure, check out the steps in this next link that can help with locating other possible backups: Locate backups of your iPhone, iPad, and iPod touch - Apple Support
If you don't have another backup available, then it would not be possible to restore your current backup until iOS 17 is released.
We hope that's able to help.
Take care.