Comment by mechanicum

These have been available since mid-2022:

  :insert-output Run shell command, inserting output before each selection.
  :append-output Run shell command, appending output after each selection.
  :pipe, :| Pipe each selection to the shell command.
  :pipe-to Pipe each selection to the shell command, ignoring output.
  :run-shell-command, :sh, :! Run a shell command

The placeholder for the current file is %{buffer_name} (not as bad as it looks, the command line has tab completion for basically everything).