Thank you for the question.
I see it works with HTML in the browser but it doesn't with pdf.
The chrome-pdf recipe just gives the HTML to the headless chrome which does pdf print so it should work there as well.
I tried to wait half a minute before hitting the printing trigger, no luck.
I tried also to use screen media type when printing, no luck.
I tried a newer version of your lib and also of headless Chrome, no luck.
There is no error printed, maybe the library has some kind of event handler you can register to?
I am afraid I don't know how to troubleshoot this further.
Maybe you rather try luck on their support forum or in the documentation
There can be some extra config you need to set to the lib before printing. Like "no animation" or something like that.
It seems they have quite a long section regarding printing here
https://enterprise.arcgis.com/en/server/latest/create-web-apps/windows/printing-in-web-applications.htm