Hyperlinks and References not working with the standalone package

I’m trying to combine two separate documents into a single document and want them to share a combined bibliography. I’m using the standalone package for the same.

main.tex

documentclass{article}
usepackage[subpreambles=true,mode=build]{standalone}
begin{document}
includestandalone{first}
newpage
includestandalone{second}
newpage
newgeometry{
 a4paper,
 total={170mm,257mm},
 left=20mm,
 top=20mm,
 }
section*{References}
bibliographystyle{unsrt}
bibliography{publications}
nocite{*}
end{document}

first.tex

documentclass[]{first}
begin{document}
blah blah blah...
href{https://tex.stackexchange.com}{Tex StackExchange}
blah blah blah~cite{Jain2021}

first.tex

documentclass[]{first}
begin{document}
blah blah blah...
href{https://tex.stackexchange.com}{Tex StackExchange}
blah blah blah~cite{Jain2021}
end{document}

second.tex is almost the same as first.tex

There are two issues with this, references to bibliography show up as [?] and the resulting document contains no hyperlinks, i.e., only the text is visible but no hyperlink is there.
Is there any way to fix both these issues?