How to bypass the FILTER function

You ask to bypass, we bypass, the old-fashioned way and by hand!

Now, with a formula:
=IF(B1=" ";" ";IF(COUNTIF(B13:B18;B1)=1;B1;FILTER(B13:B18;A13;A18=$B$1;" "))) ;
You replace filter() with:
SMALL(INDEX($B$13:$B$18,SMALL(IF($A$13:$A$18=$B$1,ROW($A$13:$A$18)-3),ROW($1:1)),"" )
This is an array formula, so it must be confirmed with
Shift+Ctrl+Enter (the 3 fingers at the same time) to display the braces.
It should automatically display between braces in the formula bar and must be confirmed the same way each time you touch it.

And you drag your formula down by pulling on the cross.

Best regards.