Why my I phone backup suddenly 10Gb become 60Gb

So I did notice What's App was not selected ...

yet we don't know if anything ... (like photos, videos, audio, or what-have-you), from what's app may be stored where those files could be backed up.

Re: why you want to access my I phone ? I don't: Yet no-one here has access to find out for you what isn't synced, in order to answer your back-up size question.

See; What does iCloud back up? - Apple Support

Eg says: Any data on your device that isn't regularly synced will be stored in your iCloud Backup.

You are in charge of what is stored:

"When you turn on iCloud for an app, its information is safely stored in iCloud and automatically kept in sync across your devices. When you turn it off, the app no longer connects with iCloud, so your data exists only on your device."

from: Change which apps sync and store data with iCloud - Apple Support

More info: iCloud User Guide - Apple Support

You can contact the experts at iCloud Support if you wish:

(There is a "Get Support" link (online chat, phone, eMail etc) at the bottom of their website: iCloud - Official Apple Support

Why my I phone backup suddenly 10Gb become 60Gb

We are all Apple users, like yourself in the community ... no-one here has access to your iPhone details.

Your screenshot shows there is 58.11 Gb in What's app

You might want to check just how much storage space is used / free on your iPhone

How to check the storage on your iPhone and iPad - Apple Support