To be clear, VMPrint isn't meant to compete with established engines like that. It’s just a genuinely helpful tool I built from scratch for the specific tasks I needed to accomplish because I couldn't find an alternative.
Prince looks powerful, but I have a feeling it probably wouldn't have been the right fit for my use case anyway.
print-css.rock [1] has a good overview of available tools and their features.
Fun fact: I had to write a routine administrative letter for my parents in another country, I asked Claude to do so in PDF form so I could email it to them they would print it and mail it. The way it did so was to write a Python program using Weasyprint to generate the PDF...
If you need something specific for a hosted service and aren't able to pay the full license fee, I can attest from personal experience that Håkon Wium Lie is very friendly and can probably work something out with you.