Hi @Flow_User ,
The preview version of the Create a task actions can do this. So you just need to swap this one out instead of using "Create a task" step and you will see the priority filed at the bottom of this step. You could get it by calling beta endpoint: https://graph.microsoft.com/beta/me/planner/tasks
It's looking for a number to set the priority here the description from MS website:
Priority of the task. Valid range of values is between 0 and 10 (inclusive), with increasing value being lower priority (0 has the highest priority and 10 has the lowest priority). Currently, Planner interprets values 0 and 1 as "urgent", 2 and 3 and 4 as "important", 5, 6, and 7 as "medium", and 8, 9, and 10 as "low". Currently, Planner sets the value 1 for "urgent", 3 for "important", 5 for "medium", and 9 for "low".
You could refer to this link: https://sharepains.com/2022/01/10/task-priority-in-microsoft-planner/
I am having the same problem. The only workaround appears to be calling the Graph API directly via HTTP call. But the authentication path and set-up is too cumbersome so it's not viable for most Low coders and non IT Admins. I guess we have to wait for Microsoft to expose this in the Planner connector for Power Automate.