I go thru the same struggle and honestly just jazz up your regular outfits. And so what if you repeat outfits? You still look good regardless, that's why you wear those outfits so much.
Wear short sleeve tshirts with long sleeves underneath. That can add so much. Try more unique pants like shades of brown, khaki, and green. Add a beanie or a baseball cap.
Wear multiple necklaces. Wear bracelets. chunky earrings. Put some gloss or lipstick on.
None of this matters if you aren't confident in yourself. Wear what makes you confident and comfortable <3