[yyyk]

>HTML to PDF is also a pain: you have to set up an instance that is running headless Chromium, which can be quite slow...

There are at least 6 non-Chromium alternative that I can think of in a moment's notice, and also LGPL wkhtmltopdf.

>Office to PDF.... You have to hack together a headless OpenOffice to have it work at all, but it doesn't do a great job... Microsoft does not offer a service to do this, unfortunately.

Microsoft sorta does offer a service to do this. Sharepoint has a word to pdf action, and with some stitching you can make it into an API. There are also several commercial solution (e.g. Spire.NET) for this and also ways exist to mangle the OpenXML into HTML (of course losing some fidelity into the process).