The best I know about is using Libreoffice. You don't really need a wrapper library for that.

You can just execute libreoffice directly using exec:

const { exec } = require("child_process");

exec("libreoffice --headless file.xyz", (error, stdout, stderr) => {
    if (error) {
        console.log(`error: ${error.message}`);
        return;
    }
    if (stderr) {
        console.log(`stderr: ${stderr}`);
        return;
    }
    console.log(`stdout: ${stdout}`);
});

You'll need to first write your DOCX to a file somewhere on the disk where Libreoffice would be able to open it, and the resulting PDF would be written on the disk as well - then you can load it into Node with fs.

I've had success using Puppeteer to render PDFs from HTML documents. If you could manage to transform your DOCX file into HTML, this might be a viable option. It looks like there are options available to do so, but I can't vouch for them.