=LET(
      c, A2:A24,
      bm, B2:B24,
      uc, UNIQUE(c),
      REDUCE(HSTACK("구분", "브랜드명"), uc, LAMBDA(a,b,
            VSTACK(a, HSTACK(b, TEXTJOIN(" / ", , FILTER(bm, c = b))) )
      ))
)