Realistically not though
The Doomslayer is strong but Sans' magic attacks the soul directly, bypassing his physical durability and speed, as well as Doomslayer only being able to throw one attack per turn, which Sans could just see coming and dodge. Considering Sans's attacks are all based around the idea of learning to predict them over the course of multiple attempts, while Doomslayer only has one, he'd be shredded by the suprise attacks, which would be even more effective due to him 100% having extremely high LV, and therefore the Karma damage would be more effective.
