When you're at rest, you're traveling through time at maximum speed (c). Start moving through space, and you "trade" some of that temporal velocity for spatial velocity, which is why time dilation occurs. Light is special only because it's massless. All of its velocity budget goes toward spatial movement, leaving none for temporal movement.
This framing makes time dilation much more intuitive than the usual "moving clocks run slow" explanation. You're not moving slower through time because of some mysterious effect. You're moving slower through time because you're now also moving through space, and your total spacetime speed is conserved.
That's the key error in thinking. The key insight of special relativity is there is no such thing as absolute time or absolute space. You have a perception of your passage of time and moving through space, but it differs from other observers in other inertial frames. There's simply no way to say what your "real" passage of time and movement through space is - that's a meaningless concept. Therefore there is no distribution of your velocity between time and space.
