Need Help - Extracting Values from a Column then Filter on those Values

Here is one way.  This will make a list of the values meeting your criteria which you can then convert to a table to be used in a slicer.  You could also use the same logic of List.Count(Text.Split([TextColumn, "."))=2 in a custom column with if..then.else to create a column to filter by in the next step.  For this one, just right click last step and "Insert Step After" and use this M code, referencing your text column name.

= List.Select(#"Changed Type"[TextColumn], each List.Count(Text.Split(_, "."))=2)

Regards,

Pat