Migration Patterns

How can we migrate files between orgs without using the Migrate function on the project in Manager? I have tried various methods to read/delete/browse/write files in the source and target orgs with and without accounts that have full access to the source and target orgs. But the files can only be seen by snaps and in Manager when the snap that creates or reads them is executed in the same org. The files can be successfully written by the source org into the target org but snaps executing in the target org cannot see them and vice versa. (Permissions cannot be set on SLDB files by the File Writer snap.) Nothing is working unless I create separate pipelines and tasks for each function (Directory Browser, File Writer) on the target org and call those from the source org with the Rest POST snap so that they are executed on the target org. This seems extremely complicated for a seemingly simple task of deploying files. What am I missing?