Retrieving the date when a value changes for current and following rows

PMons88 , try this calculated column:

DESIRED OUTCOME = 
VAR vJobCat = 'Table'[JOB CATEGORY]
VAR vDate = 'Table'[DATE]
VAR vEmpID = 'Table'[EMP_ID]
VAR vLastDateWhenJobCatWasDifferent =
    CALCULATE (
        MAX ( 'Table'[DATE] ),
        FILTER (
            'Table',
            'Table'[DATE] < vDate
                && 'Table'[JOB CATEGORY] <> vJobCat
                && 'Table'[EMP_ID] = vEmpID
        )
    )
VAR vFirstChangedDate =
    CALCULATE (
        MIN ( 'Table'[DATE] ),
        FILTER (
            'Table',
            'Table'[DATE] > vLastDateWhenJobCatWasDifferent
                && 'Table'[EMP_ID] = vEmpID
        )
    )
RETURN
    vFirstChangedDate

When I try it with your sample data it gives these results:

By the way, it looks like the DESIRED OUTCOME column is wrong for months Apr-22 and May-22. When the Job Category changes from AAA to CCC on 1 Apr-22, I believe you want the new column to show 1 Apr-22 for rows with the date is 1 Apr-22 and 1 May-22.