passing filter options with the --convert-to CLI switch to soffice?

Maybe I understand what you're attempting; I'm confused about
whatever CLI switch is though.

       I've only converted PDFs to Word and all appears fine,
          so unless there's a bug in your program version, I don't see why
reversing the process should be a problem.

       Have you checked to see if others have reported a bug?; if not, then
maybe doing so, as a query, might bring someone to offer help,

       Maybe I understand what you're attempting; I'm confused about
whatever CLI switch is though.

A "CLI switch" is an sub-command or option that can be specified on the
command line as part of the command-line interface (CLI).

       I've only converted PDFs to Word and all appears fine,

But perhaps you are not using "filter data" options?

          so unless there's a bug in your program version, I don't see why
reversing the process should be a problem.

No, what I'm wondering about is how I specify that I want the generated
PDF to be tagged (a modern-day requirement for compliance with
accessibility regulations).

Running "soffice --help" on the command line gives me this (plus much
other information):

--convert-to output_file_extension[:output_filter_name[:output_filter_options]] [--outdir output_dir] files
      Batch convert files (implies --headless).
      If --outdir is not specified then current working dir is used as output_dir.
      Eg. --convert-to pdf *.doc
          --convert-to pdf:writer_pdf_Export --outdir /home/user *.doc
          --convert-to "html:XHTML Writer File:UTF8" *.doc
          --convert-to "txt:Text (encoded):UTF8" *.doc

In the last couple of examples, I think "UTF8" is a filter option. But
it doesn't have the name=value form. So I'm wondering how it's supposed
to work. And where it's documented.

Bill