Extract unique dates from a list through formula only

Select the raw data and choose Insert>Pivot Table.
You can then sum up your data in various ways.

Have a go with a mock file if you haven't used Pivot Tables before to see what you can do, hopefully this will provide the solution to your problem

Use a Pivot table as previously suggested. An example is attached.

Or in a table that extracts unique dates, say A3 Down
In A3

Formula:

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Use this as the Data Validation list in G3 down.
See the Names Manager for how to make this list dynamic.

Select from the options in G3:I10

Does Post #4 not suit your needs?
It uses formulae only.

If not please explain why not.