I'm trying to use dtutil to automate the migration of hundreds of packages from SQL Server 2016 to SQL Server 2019 in another server.
It seems dtutil is unable to find the project/package folder.
All I found in docs and links seems to refer to msdb, but here, the folder/project/package data is stored in SSISDB database tables instead.


I don't think you can use DTUtil to migrate packages from SSISDB.
Based on the official documentation:
Alternatives
There are several alternatives to migrate SSIS projects from SSISDB to another instance such as backup and restoring the SSISDB database, using a third-party solution, or using the Package import wizard.
You can refer to the following articles for more information: