That doesn't work either; xattr doesn't seem to support either the c or r options in macOS 11.5:
xattr -cr /Applications/RocksmithTool.app
option -c not recognized
usage: xattr [-slz] file [file ...]
xattr -p [-slz] attr_name file [file ...]
xattr -w [-sz] attr_name attr_value file [file ...]
xattr -d [-s] attr_name file [file ...]
The first form lists the names of all xattrs on the given file(s).
The second form (-p) prints the value of the xattr attr_name.
The third form (-w) sets the value of the xattr attr_name to attr_value.
The fourth form (-d) deletes the xattr attr_name.
options:
-h: print this help
-s: act on symbolic links themselves rather than their targets
-l: print long format (attr_name: attr_value)
-z: compress or decompress (if compressed) attribute value in zip format