Alternatively using native Blue Prism functionality:
Choice Stage
Choice - FormatDate(Today(), ""dddd"") = ""Saturday""
Calculation Stage if True - ToDateTime(AddDays(Now(), 2)) + MakeTimeSpan(0 ,[Hours], [Minutes], [Seconds])
Choice - FormatDate(Today(), ""dddd"") = ""Sunday""
Calculation Stage if True - ToDateTime(AddDays(Now(), 1)) + MakeTimeSpan(0 ,[Hours], [Minutes], [Seconds])
You can initialise the [Hours], [Minutes] and [Seconds] data items to 0, or provide based on time you want to defer until on Monday. Or alternatively hard code within calculation stage.
These calculation stage will then output to a DateTime data item that can be used as the input to your Defer action.