Can multiple PDF files use the same FillPDF form?

No, each form needs to have its own PDF file.

Thank you! Pretty glad to hear that, really, because i had already started making a module to work around that for this use case, heh: FillPDF Comprehensive Mapper, https://www.drupal.org/project/fillpdf_comprehensive_mapper →

Should have that done soon, things got in the way, and i'll think about where it makes sense to document the architecture of FillPDF— it's both obvious in the way the filling is set up but also not 100% clear that passing in another parameter might be a hidden capability.

Thanks

By the way, you could shorten your SettingsForm class by using constructor property promotion.