Explanation
https://docs.microsoft.com/bs-cyrl-ba/azure/sql-database/sql-database-managed-instance-migrate Quote from that page "Azure SQL Database and SQL Server databases in an Azure Virtual Machine. DMS is the recommended method of migration for your enterprise workloads.
If you use SQL Server Integration Services (SSIS) on your SQL Server on premises, DMS does not yet support migrating SSIS catalog (SSISDB) that stores SSIS packages, but you can provision Azure-SSIS Integration Runtime (IR) in Azure Data Factory (ADF) that will create a new SSISDB in a managed instance and then you can redeploy your packages to it, see Create Azure-SSIS IR in ADF.
To learn more about this scenario and configuration steps for DMS, see Migrate your on-premises database to managed instance using DMS."
https://docs.microsoft.com/en-us/azure/data-factory/how-to-migrate-ssis-job-ssms