PDF / A3 format

Assalam elikum,

We’re currently exploring options for generating PDF/A-3 compliant documents but, unfortunately, haven’t found any reliable open-source solutions (in Java or otherwise) that meet the requirements. We’re interested in learning what other community members are using for compliant PDF/A-3 document generation. Are you relying on paid solutions, or have you found any effective open-source options?

Thank you,
Farhan

On dotnet c#
We are using PDFNET.dll