For me putting this in the Extra field works:

tex.origdate: 1972

original-date: 1972 Should work well based on the links below. But I have the same problem as you. Hope @emilianoeheyns could help.

The "solution" of tex.origdate is problematic because the original date is added to the bibtex file but Zotero does not recognize it. So if you use the zotero plugin inside libreoffice or any other word processor, the original date won't be reflected in the citations or references (and the same problem appears when you try to "Create Bibliography from item" inside Zotero).

I am using Zotero 7 with the latest betterbibtex: 6.7.226

https://retorque.re/zotero-better-bibtex/exporting/extra-fields/
https://github.com/retorquere/zotero-better-bibtex/issues/1696

Indeed, with the "Better BibTex" plugin and export-format, I manage to create a bibliography ! Thank you. [Zotero 7 with the current betterbibtex plugin]

When you are exporting, is the format you are choosing called “Better BibTeX” or just “BibTeX”.

“BibTeX” (no Better) is Zotero’s built-in export format intended primarily for data transfer, and it doesn’t extract CSL fields from the Extra field

If help is still needed, please open an issue at https://github.com/retorquere/zotero-better-bibtex/issues