i've been playing some activities and happened to have enough materials to upgrade one of the armor pieces, so i did it. I upgraded the arm piece on my hunter just to check the glow. Then i went to the eververse store to check what i could buy. I checked the coloured glows and noticed i could buy for bright dust. I don't know if it is a bug or intended, but i could do it. Do just enough to upgrade one of the armor piece, and then you should be able to buy the glow with bright dust. I could, on PS5.