Hi, and thanks for reaching out.
Is it possible that when you zipped the archive you either missed that file, or zipped at the wrong level? I can repro that by zipping the top directory instead of going into it and zipping the contents (.xml files, lists/queries/other folders).
That said, this migration between servers referencing users by account ID is not supported, as those IDs (as you noticed) will not be consistent across systems. You might have luck by changing to use a text name in that "Data Steward" field, then adding a query layer on the new server to remap to those names in the new core.users table. Another option would be to start an entirely new separate instance using a clone/backup of the original server's database, similar to the process for creating a staging server. You could then delete all the projects and folders except the one(s) you are trying to move to the other instance.
Hopefully one of those ideas helps,
--Molly