Deleting an iCloud Backup of an iPhone will not delete data from any devices (including the iPhone).
Also note that Contacts, Calendar and Notes are typically synced to iCloud via the options in Settings > [username] > iCloud and if they are synced to iCloud they are not also included in an iCloud Backup. See below from What does iCloud back up? - Apple Support
Your iPhone, iPad, and iPod touch backup only include information and settings stored on your device. It doesn’t include information already stored in iCloud, like Contacts, Calendars, Bookmarks, Mail, Notes, Voice Memos3, shared photos, iCloud Photos, Health data, call history4, and files you store in iCloud Drive.
And be aware that any change (including deletions) that you make to synced data on any device or on iCloud is synced to all of the devices where that syncing option is on and to iCloud.