Sri Krishna Sweets in Al Qusais is a must-visit for Diwali sweets. They're known for their milk Mysorepak, which melts in your mouth and is the best even in India.
As a gift, you can consider getting their gift hampers with different types of sweets in a box. They also have 'mixtures' which are a combination of smaller spicy snacks that come together to make for a really good snack overall.