iCloud backup size massive
Recently purchased an iPhone 13 as an upgrade from iPhone 8. When I have come to backup my new phone, my backup size is registered as being 18Gb, which is massive and much more than anyone I know. This means that I am unable to backup my phone to iCloud through not enough storage space (using 50Gb currently and not looking to upgrade). Even with all apps I have downloaded deselected through the 'manage account storage' page in iCloud settings the backup size is still 13Gb (This saves about 5-6Gb which I'm led to believe is the normal amount of backup size). Any ideas as to where this huge backup size is coming from and how to decrease it significantly. The only idea I have remaining is to delete the saved 16Gb backup from my old iPhone 8, however am reluctant to do this as this would leave me with no backups whatsoever.
Any help would be greatly appreciated.
iPhone 13, iOS 16