Power Query: Identifying duplicate unique values and retaining the latest entry based on date and time

You can try this in M/powerquery (note sample output in question is wrong)

Right click Unique ID, group by, using operation all rows

In formula bar remove everything betweeen and including the [] brackets

Sort the data table, so _ becomes Table.Sort(_,{{"Date", Order.Descending}})

Take the first row of that (now the largest date) so it becomes Table.FirstN(Table.Sort(_,{{"Date", Order.Descending}}),1)

Click the arrow atop the new column and expand it

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Total sample code, you can paste into home...advanced editor..

let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Grouped Rows" = Table.Group(Source, {"Unique ID"}, {{"data", each Table.FirstN(Table.Sort(_,{{"Date", Order.Descending}}),1), type table }}),
#"Expanded data" = Table.ExpandTableColumn(#"Grouped Rows", "data", {"Date", "Total"}, {"Date", "Total"}),
#"Changed Type" = Table.TransformColumnTypes(#"Expanded data",{{"Date", type date}})
in  #"Changed Type"