Can iCloud backup be done with cellular dataCan iCloud backup be done with cellular data

Only with some carriers using 5G on newer iPhones that support 5G cellular. See the following from Back up iPhone - Apple Support

Note: On models that support 5G, your carrier may give you the option to back up iPhone using your cellular network. Go to Settings > [your name] > iCloud > iCloud Backup, then turn on or off Backup Over Cellular.