for cult party kei, i would recommend layering a lot of cream colors, with some warm peach tones and pink mixed in, as well as gold accessories, to really make the orange bag flow well with your other pieces.
for fairy kei, i would go for orange’s contrast color–a lavender purple, and also use creams to get a more pastel look, adding in the bright orange of the bag into smaller accessories for the look such as hair accessories, glasses, socks or shoes, jewelry such as enamel pins or scarves. using a few bright colors sparingly is common in fairy kei, and as long as you keep the overall colors pastel and dreamy i think you can still work it out!
for mori kei, i think working in the orange would be really easy! just go with nice caramel brown accents, or even some more orange-y shades like a pumpkin color, as well as black, cream, and forest green to make the purse fit the overall earthy vibe!
then for just street fashion, a lot of options are possible! my first instinct was to pair it with cream and black, and then bring the orange back in similarly toned brown shades to make it work!