Using Pivot Table @ ANALYZE IN EXCEL, the "Number Format" @ "Field Settings":
Working as usual @ VALUESS area "Missing" @ both ROWS area and COLUMNS area
Also, the formats of certain fields (like Date) do not seem to follow PBI model's format after connecting to ANALYZE IN EXCEL.
For example, my Date is formatted as "Date" in PBI model, but it seems to be in "text" format here. Without the ability to change the format at Pivot Table (described above), DATE column at Row Field cannot be used for "Timeline Slicer".
@JohnBI, I personally think what you get is correct that we can only change number format for metrics in the PivotTable. For your issue, you can put your date column to the Filters then you can filter the data based on date.