How to automate Planner and integrate it with Power Bi

I agree about using Flow to export data to SharePoint lists. I find that helpful for SCRUM teams that want to use Planner. There are some frustrations with that though, as not all the Planner fields are available to Flow (specifically, the multi-value fields like labels and checklist). If those aren't important to you, then that'll do fine. I'm curious how you'd measure the duration of a Planner task. In many cases, I find that tasks are created / staged well in advance of when they're going to be worked on. Would you try to look at the Planner 'created'  value, or would you push things to SharePoint frequently as they're moved to 'In Progress' and then look at the SharePoint created date? Just thinking out loud - I don't have a well thought out recommendation for this.

Here's an answer for the 'clone tasks' part of your question. You can do use the 'copy task' menu command for this. Either copy a completed task or setup some dummy tasks with generic names in a separate bucket. Then move the copies to whatever bucket you want for tracking.