Hi @chhe :
Could you tell me:
Do you want to get a dashboard like this?

Does your “AssignedTo” field allow multiple selections?
I’ve made a test for your reference:
I assume the “AssignedTo” field does not allow multiple selections.
Here is my data source :list4

Step1:add a gallery and set it’s items property to :
GroupBy(ForAll(list4,{AssignedTo:AssignedTo.DisplayName,Title:'Title',time:time}),"AssignedTo","Image") /*image is a new column name created by groupby function*/

Step2:add a pie chart control into this gallery and set it’s text property to:
ThisItem.AssignedTo

Set it’s Items property to :
ThisItem.Image

Set it’s Items property to (This formula should be filled automatically):
ThisItem.Image.Title

Then you will get the result.
Best Regards,
Bof