Hi Luoooofei,
The issue you’re encountering may be due to the “discountApplicationStrategy” set as “MAXIMUM”. The “MAXIMUM” strategy applies the highest possible discount to the cart. If you have multiple discounts, it won’t apply all of them, but only the one with the maximum value.
If you want to apply multiple discounts to different products, you should consider changing the “discountApplicationStrategy” to “ALL”. This applies all discounts to the cart. Note that the order of discounts in the array can affect the final price, as discounts are applied in the order they appear in the array.
You might also want to double-check your product variant IDs to ensure they are correct. Hope this helps!