I've been using paperless-ngx to manage all my documents, but every once in a while I'll get a .docx file to deal with...
Turns out Libreoffice has a headless mode a pdf converter built-in!
libreoffice --headless --convert-to pdf /path/to/file.docx --outdir /path/to/output/directory
Note that
--outdiris in fact a directory, not the path to a file