Texjoin to remove duplicates

Hello,

Attached file I'm having issues with.

I have a column with list of units that includes duplicates. Next to that column is a list of Ages with more duplicates. For example, for said unit 1203, I have in column A 17 rows with that same unit number. In column B, I have 16 rows showing age 39, and one row showing age 34.

In column F, I have all the units where I removed duplicates. Next to it in column H actually, I am trying to use the textjoin to see the ages without any duplicates. In example above, I need to see 34,39.

Here is the formula I am using in H2.

=TEXTJOIN(",",TRUE,IF(($A$2:$A$683=$F2)*(MATCH($B$2:$B$683,$B$2:$B$683,0)=(ROW($B$2:$B$683)-ROW($B$1))),$B$2:$B$683,""))

Please help. File is attached. Thanks in advance.