TEXTJOIN with ARRAYFORMULA Google Sheets

 

Here Is the Formula :

=ARRAYFORMULA(IFNA(VLOOKUP(A2:A&"",TRIM(SPLIT(REGEXREPLACE(TRIM(FLATTEN(QUERY(QUERY({J2:J&"♥", L2:L&","},"SELECT MAX(Col2) WHERE Col2 <>  ',' GROUP BY Col2 PIVOT Col1"),,9^9))), ",$", ), "♥")), 2,0)))

Example : Sheet Link