Εxlude products from discount

Hello,

No not directly, but there are a solution maybe you can use.
For this you have to create a another category in your parent categories, and associated required products just for your discount.
In details :
1° You have your selected category, "Category A"
2° Create your new category, "Category A-discounted",
=> Take care to place your new category in an appropriate place to prevent it from appearing for example in one of your product
listings, the best way to do this is that this category is not a parent category.
3° Associate to your new Category ("A-discounted") all your required products.
4° Use this new category for your Discount restriction

Hope this will help you to achieve your needs.
Regards