I see alot of people who just use the index, middle and ring fingers when they’re playing on their sticks. When it comes to throwing or focusing I seldom see players use their thumbs? Why not? They were made to help your fingers for a reason and they help if you don’t have the fastest reactions.
I personally use my thumbs for lk and mk, although if I need to plink mk for a link I’ll use my index and middle finger.