Hi and welcome to the forum

INDIRECT() can be used to "convert" any text into a format that excel will understand. However, INDIRECT only works on open workbooks.

The formula might look something like this...

=INDIRECT("'[workbook"&row(A1)&".xlsx]sheet"&ROW(A1)&"'!$I$53")/1000 (untested)

There is an add-in called Morefunc that modifies INDIRECT() to allow its use with closed workbooks