Pages v12.1 on macOS Big Sur was the last version of Pages to offer dual export to docx/doc. On Sequoia, your option is to export to docx from Pages and then open that document in either of LibreOffice Writer 25.8.1 and then save as Word 1997 - 2003 (.doc) format, or open it in Microsoft Word (e.g. v16.100.3) and save as Word 1997 - 2004 (.doc) format. Be certain that you select the macOS (Intel) version of the software above the yellow download button for LibreOffice.
Abandon the notion of using an older version of Pages on Sequoia, and abandon any entity still requesting Word documents be submitted in the .doc format. The rest of the civilized world has been standardized on Word .docx or the OASIS OpenDocument (odt) formats for over two decades.
Also, note that a saved .doc document is not previewable with the Finder's Quick Look on Sequoia v15.6.1.