I have an alternative approach that uses Offset() to start a list from a point in the text entered in a dropdown cell.
For example, with a list of countries typing, Can might start the list with Canada . Just type C start with Cambodia .
Please note that for this you need to turn off the error warning.
The key is to use the formula as shown below as the source of the list.
=OFFSET(<I>CountriesListFirstCell</I>,MATCH(<I>DropDownCell</I>&"*",<I>CountriesListcolumn</I>,0)-2,0,COUNTA(<I>CountriesListColumn</I>)-MATCH(<I>DropDownCell</I>&"*",<I>CountriesListColumn</I>,0)+1,1)
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