I believe your goal is as follows.
In this case, how about the following sample formula?
=ARRAYFORMULA(IF(D3:D<>"",REGEXMATCH(D3:D,TEXTJOIN("|",TRUE,C3:C)),""))
=IF($D3="",,NOT(ISERROR(REGEXEXTRACT(LOWER($D3),JOIN("|",FILTER(LOWER($C$3:$C),$C$3:$C<>""))))))
I found this answer to my question based off of this old question.