Solve Chart Exceeded rows limit

Summary:

Due to removal of Learn subject area in 22d, i am recreating my reports using the alternative however there is one feature that I cannot replicate.

The original chart automatically reduces its return based on the first item in the column in the original report however it does not have a prompt included.

I have tried to replicate using a prompt however it will not return the first item and so errors however when in chart edit mode, it does.

I have attached screen shots and the code below for ease of reference.

Any ideas how to solve please?