I need a more precise way to detect entity collisions for my datapack

I'm working on my first big datapack project, and I have a pretty integral battle system for it in the works, however, I'm noticing that despite the hitbox of my soul entity (which is about as big as the sprite you see) being rather far from the hitboxes of the projectiles, its still acting like I've been hit, and I'm thinking its something to do with the way the collision detection is set up. In order for this system to work, I'd need a more precise way of detecting collisions, but I'm still fairly inexperienced with making datapacks, so I don't know of any better alternatives