o i have to upload and run a script with its default value first (since I don't have an initial task id), then clone it, edit the configuration inside that newly cloned one, get the id of the clone, and pass this into my script as the task_id and run it from my machine?

Correct. You can also create it (from code), "Reset" it (right click in the UI) and then edit it.

Is there a way do this without running it on my machine?

check clearml-task it is a CLI that will create a Task from the code on your machine/repo and enqueue it for you 🙂
https://clear.ml/docs/latest/docs/apps/clearml_task