Hey L Girl,
We'd be happy to help. While we cannot speculate on why your backup size is what it is, if it's exceeding the device storage size, you won't be able to restore it until freeing up enough space. For more info, check out the following details:
If an alert says there's not enough disk space
If a message says there’s not enough disk space when you try to back up your device, free some space on your Mac or PC. If you still see a disk-space error after you free enough space, contact Apple Support.
This is outlined further here: If you can't back up your iOS or iPadOS device to a computer or restore it from a backup - Apple Support
With all that being said if you want to manually get back as much as possible, do you sync any data to iCloud? If so, you can still get that information back by signing into iCloud and enabling Contacts, Calendars, Reminders, Messages, etc. Be sure to enable all that you need and have synced.
Afterwards, you can redownload any apps, games, music, tv shows, etc using the steps in these resources:
Redownload TV shows and movies that you purchased - Apple Support
Redownload apps and games from Apple - Apple Support
We hope all this information helps out.
Take care!
