Extract mm.yyyy from text

Hi SDj1​ 

Your examples were definitively required as your pseudo-dates are not always in mm.yyyy format as you initially said. Anyway, with your example in B2:B21 below (pic. cropped)

in D2:

=LET(
  afterDated,   TEXTAFTER( B2:B21, "dated " ),
  beforePdf,    TEXTBEFORE( afterDated, ".pdf" ),
  TRIM( TEXTBEFORE( beforePdf, " invoice ",,,, beforePdf ) )
)

Attaching a sample file & crossing fingers it won't be dropped by this site...

EDIT A variant that replaces months in MMMM format with their corresponding number:

With a LAMBDA named EXTRACT_DATE stored in the Name Manager, in F2:

=EXTRACT_DATE( B2:B21 )

where EXTRACT_DATE is:

=LAMBDA( reference,
  LET(
    seq,          SEQUENCE( 12 ),
    months,       TEXT( DATE( 2000, seq, 1 ), " MMMM " ),
    replacer,     IF( seq < 10, ".0" & seq, "." & seq ) & ".",
    EXTRACT,      LAMBDA( rw,
      LET(
        searchMonths, IFERROR( SIGN( SEARCH( months, rw ) ), 0 ),
        monthsAsMM,   IF( SUM( searchMonths ) = 0,
                        rw,
                        SUBSTITUTE( rw,
                          XLOOKUP( 1, searchMonths, months ),
                          XLOOKUP( 1, searchMonths, replacer )
                        )
                      ),
        TEXTBEFORE(
          TEXTAFTER( monthsAsMM, "dated " ),
          {".pdf"," invoice "}
        )
      )
    ),  
    BYROW( reference, EXTRACT )
  )
)