My bad i missed the version
Only option you have is using orchestrator manager..but even that does not migrate test cases
Instead of creating manually..one advise i can give if the amount of test sets are huge to use orchestrator api calls to read from classic and then create in modern folders..can check swagger for details..
or another way is first upgrade the orchestrator to 22.10 and 22.10 provides a wizard which can be used to migrate
Cheers