No, you can not just copy over the files with winscp, thats why there is the migration tool to move from one host to another 😉
But the path with the migration tool should not be that longer / more complex.
You can do a two step migration:
1. Create a migration file on the source server
java -jar dynatrace-migration.jar -migration -sourceDTHome "<DT_HOME_OLD>" -targetArchiveDir "<ARCHIVE_DIR>"
2. Copy the file (its just a zip file with a different extension, "dtma") to the target server using scp
3. Import the migration file to the target
java -jar dynatrace-migration.jar -migration -sourceArchive "<ARCHIVE_DIR>/<MIGRATION_ARCHIVE>" -targetDTHome "<DT_HOME_NEW>"
You give an archive directory (-targetArchiveDir) on the "export" step and it creates a dtma file in that directory.
You copy that dtma file to the target server and use whatever directory you like.
You then reference the full path to that file (-sourceArchive) in the "import" step.