The `xargs` utility on Mac is not the same as the one on linux. In particular, searching for files with the `mdfind` utility will not properly escape files to be processed.
Using `homebrew` you can install the GNU version of `xargs` as `gxargs`, and you can use the syntax you’re accustomed to from GNU/Linux.
For me this is equivalent to something like:
mdfind -name “conflicted copy” | gxargs -d ‘\n’ -P 4 echo
To remove the files you can then replace `echo` with `rm` – but be careful!