We need to promote contents from one DB to another? How is this done? We need to automate and have a schedule job for this process

How to “package” up release and promote to various environment without refreshing the whole DB to effectively populate new page type / contents / DB changes up with any no loss of data and not overwrite the current target contents/pages.
The target should treat the source content/pages as a new content/pages.

Please help.
Thanks
Kavi