There are many possible solutions. Please post a sample sheet (no pics please) where the patient's name/ ID have been anonymized, but without changes to the dates, as they might be text looking like dates, not real dates ( formatting is how dates are presented to the outside world, it's the underlying data that is important.
If, after removing eventual manual alignments, your dates are left aligned in the cell, they are text ( although they look OK) requiring some additional treatment

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