can i ask what you are actual trying to do from a business perspective what is the requirement.
There are many ways to handle this data from a modelling perspective.
I would potentially apped the tables in powerquery. However that depends on what your end game is.
If you merged the tables,
first you would add a new column to both tables,
to table 1 with date1 you add a flag column = 0
the table with date2, you could add flag column= 1
then when you append the tables you will know where to start, however reading through the examples you have provided it does not make sense.
I do not see any date with 08.12.2021
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