cannot create identical copy of installation big sur mac

[ale82to]

first of all sorry if the issue is not a but it s bee a week i ve been trying to clone my big sure installation(i don t need it to be bootable) but rsync will run untill it fills the usb backup volume not finishing the clone task. here s the flag i used: sudo /usr/local/Cellar/rsync/3.2.3/bin/rsync -xrlptgoXvHS --progress --update --delete-before --fileflags --exclude={"/dev/","/proc/","/sys/","/tmp/","/System/Library/dyld/","/mnt/","/media/*","/lost+found"} my set up is quite "tidy" all my digital life is 90 gb including app and system folder ,machintosh hd is a 256 gb ssd ,usb disk is 120 gb (considering i ve excluded dyld folder which is almost 10 gb ) free space should not be an issue ,still with above command rsync will fill usb hdd untill it stops. can please someone tell me if its a bug or more likely i m making some mistake in the command above thank you very much for the help. ps : source:/ dest:/Volumes/backup