How exactly does iCloud backup?

[AMSOS]

Hi. I tried keeping track of all the changes that have been made to iCloud these past few years, but looks like I am a bit lost at this point.
If I switch on E2E on iCloud, can I just setup my friend's phone number as a recovery number, so I can get access to my iCloud data in case I forget the relevant password?

Can you point me to a web link that clearly indicates all the apps-system or otherwise-that use iCloud storage space? e.g., I can see that any app on my iPhone tries to allot its own space on iCloud, but it's unclear if iCloud Drive also uses this space.

Do any of you still prefer the old way of backing up to your computer, and mostly avoiding the cloud? Other than the obvious issue of convenience, is there any other disadvantage with backing up like this?

 

[Bigwaff]

so I can get access to my iCloud data in case I forget the relevant password?

Yes. You can have multiple trusted phone numbers.

Do any of you still prefer the old way of backing up to your computer, and mostly avoiding the cloud? Other than the obvious issue of convenience, is there any other disadvantage with backing up like this?

iCloud not backup service. It is a file syncing service. So, yes, one should backup local or to cloud using backup software, e.g. Time Machine (local) or Arq (to cloud).. examples but there are many others.

Note: Hasty post as I was obviously thinking macOS. For iOS, examples one can use iMazing to backup iPhone,iPad,to local disk or to mounted cloud storage.