Since I can remember, WhatsApp has always had 2 options when it comes to backing up your data on iOS:
Option 1 (Backup with Device Backup)
Settings>Apple ID Settings>iCloud>Manage Storage>Backups>Your Device>Choose Data To Backup
This option is on by default and what it does is whenever your device backs up to #iCloud all of your #WhatsApp #data is backed up along with it and when you restore to a new device all of the data restores as it is.
Option 2 (Backup on iCloud Drive)
Settings>Apple ID Settings>iCloud>Bottom of The Page
This option can be controlled within your WhatsApp settings and you can choose if you want to backup your videos or not and the backup frequency also. This option is separate from your device backup and is linked to your WhatsApp account number.
Now ideally you would want both to be on if you want to be safe about your data and never ever want to lose it. But iCloud only gives users 5GB free and having 2 backups of the same thing is kind of redundant.
So let me try to explain which one should you choose.
Option 1 is over all more reliable but it only works if you restore your device backup to a new device, so if you just log in to a new WhatsApp you can’t restore from this backup, it only works when you setup a new device and choose the restore from iCloud option.
Option 2 is linked to your mobile number, so whenever you login to a WhatsApp account it will check with the device apple ID and see that you have a backup in the drive and give you the option to restore, the problem is often times this restore is not completed and you end up losing media.
So I prefer option 1, but if you juggle a lot of devices option 2 is preferable.
On #Android side you only have option 2, as Android doesn’t create whole device backups on most brands. So you only have the option to backup to #GDrive similarly to iCloud drive and the backup is linked to your mobile number.
Yes I know this is complicated information, but WhatsApp has become an integral part of many people’s life recently. Hope this helps.