Hi @jeyeline,
In that case it might be easier to just use a query for this. You can use that in a Get query results action.
Below is an example
1. Below is the sample Aging work items query

2. Below is a flow setup.
3. First A Select is used to get a list of people which are assigned to work items
4. The apply to each uses a union function to get a distinct list of assigned to people to loop through
union(body('Select'),body('Select'))
5. A filter array is used to find all items matching to the current assigned to user.
@equals(item()?['System.AssignedTo'], items('Apply_to_each'))
6. A condition is used to check how much items this person has (3 or more)
length(body('Filter_Array'))
7. If that is the case an email is sent.
slice(items('Apply_to_each'), add(indexOf(items('Apply_to_each'), '<'),1), -1)
