LyX: Missing menu entry for export to docx

I have LyX 2.3 installed, and my understanding is that LyX > 2.2 should have an option to export to *.docx out-of-the-box (e.g. “File > Export > MS Word Office Open XML”). But for me, that menu item is missing.

Interestingly, when I look in the “Preferences > File Handling > Converters” dialog, there is a converter for “LaTeX (plain) -> MS Word Office Open XML”:

pandoc -s -f latex -o $$o -t docx $$i

If I have LyX export a *.tex file, and then use the above pandoc command on that *.tex file, I get a successful conversion to *.docx. So I know that pandoc is installed properly and that LyX is aware of it.

Also interestingly, if I add a new converter for “LaTeX (XeTeX) -> MS Word Office Open XML” with the exact same pandoc command (so the only difference is that it’s converting from “XeTeX-style” latex instead of “plain” latex), the expected export menu item appears. The exported document has “@/path/to/directory/containing/lyx/file” on the first line (which wasn’t present when I manually ran pandoc on the command line), but looks otherwise correct.

I also tried adding a “LyX -> LaTeX (plain)” converter (since there wasn’t one to begin with) with the idea that maybe LyX just didn’t know how to convert to LaTeX (plain) for some reason, but that had no effect.

So my question is: can anyone explain how to get LyX to recognize plain LaTex exporters? It’s not a dire problem, I have the XeTeX hack (even if it adds a weird header for some reason), and I can always run pandoc from the command line. But it seems like something that should just work, no questions asked.

Edit:

Here are some relevant lines from my configure.log file:

INFO: checking for a LaTeX -> RTF converter...
INFO: +checking for "latex2rtf"...  yes
DEBUG: Add to RC:
converter latex      rtf        "latex2rtf -p -S -o $$o $$i"   "needaux"


INFO: checking for a LaTeX -> Open Document (Pandoc) converter...
INFO: +checking for "pandoc"...  yes
DEBUG: Add to RC:
converter latex      odt3        "pandoc -s -f latex -o $$o -t odt $$i"    ""


INFO: checking for a LaTeX -> MS Word Office Open XML converter...
INFO: +checking for "pandoc"...  yes
DEBUG: Add to RC:
converter latex      word2       "pandoc -s -f latex -o $$o -t docx $$i"   ""