TextJoin but removing duplicates and ignoring blanks

Hi,

I want to list values only ONCE from one column even taking into account multiple values may occur within each cell.

e.g.

AC2 contains dog cat horse cow sheep
AC3 contains pig bird deer
AC4 contains bear cat fish snail

I only want 'cat' listed once.

Some rows will also be blank as yet to be populated by the lookup in place.

I have started to use:

=TEXTJOIN(" ", TRUE, IF(MATCH(AC2:AC44, AC2:AC44, 0)=MATCH(ROW(AC2:AC44), ROW(AC2:AC44)), AC2:AC44, ""))

but of course it considers the content of the entire cell - not each string within it - before removing duplicates...

Any ideas?