In theory a star fish is also slower, but a garden snail is a certain variety that is the slowest snail.
Slugs are faster, mainly because they don’t carry their house on their back, and also because they need to be to get away from predators, whereas snails hide in their shells.
Garden snails are slower than giant tortoises which I considered, but thought garden snail is a 2 or 3 hopefully you pick the right number and you did!