Hello
Joomla is arranged so that articles data are also recorded in the additional table "assets", so we do not have to copy database tables from one database to another, but we need programmaticly create an articles. In this case, the old data in advance must also be deleted. Otherwise a collision may occur in the "assets" table and your articles will become inaccessible.
I regularly do data migration for Joomla and can help you with the correct transfer of articles.
Sincerely, Boris.