Many years ago i test many HTML/XML To HTML/PDF converter and it was a nightmare ( FOP , python, xpath, xslt). So beautifull web site and hight cost but none was really efficient .
Manifold do have a asp Web JS jSscript server for their IM Server in M8 ( ims page , IMS_prog_examples.zip ) to convert their geom to SVG and i study it and like how matrix was use to manage reference coordinate and each geom type ) and create a desktop M8 custom script. I think this could appear when see how OScar from mediachance achieve this in their tool call Realdraw . I contact him for an update because with time SVG converter has too many issues , but a deprecated software not maintain anymore. I create a post about this IMS demo here and here ( search for "ims demo" )
For pdf printer i have issue like link but i think there is many ....
Here a small list of pdf virtual printer starting from wikipedia page .
perhaps one ll be better and suitable for you need ( not too many errors ).
Universal Document Converter https://www.print-driver.com/
Nova PDF https://www.novapdf.com/
Do PDF https://www.dopdf.com/
Primo PDF https://www.primopdf.com/
Pdf 24 https://en.pdf24.org/
Cute PDF https://www.cutepdf.com/index.htm
Pdf 995 http://www.pdf995.com/
Soda pro https://www.sodapdf.com/
i ll test some but it ll be really great if a manifold project demo that use the more functionnalities that manifold support in term of rendering text image vector (text , shape/geometry , line colors, link , layers, color, motif style, texte , icon, label). So any can print pdf with it own pdf printer !!
I think pdf editor matters even we can't edit really pdf ( we edit group of character line area) so i think name the pdf editor you have for test should be write : I ll test with serif affinity designer ( vector) and XpagePlus, adobe illustrator CS6 (never go to subscription model) . I don't havefoxit Phantom editors licence even i like it for the limit time i could test. Foxit have pdf server for form and search plug in for pdf so i think their are really pdf specialist for pdf/form. Microsoft MVP in their blog use foxit with script and i like foxit even there was malware in the past .
THere is many way to code SVG rendering in browser . I test them there is many years so i need to update my knowledge about this !