it's a shame Acrobat doesn't have this feature. I think Adobe could think of incorporating it. This would be very interesting for composing documents that are worked on by different users or worked on until the last moment. Adobe Illustrator does not do this correctly. And I haven’t found any software that does
If all the users have Acrobat, and you can install a script on their local machines, it's possible to use a script to merge the source documents "on the fly" when you click a button. You can contact me privately via [try6767 at gmail.com] if you're interested in hiring someone to develop such a tool for you.