The universe depends completely on interaction. Anything physically existing has to impact something else already existing, or else, it didn't happen.
All these exchanges and interactions shape reality. They seem to develop at the speed of light to us (material observers), but are instantaneous for the massless carriers involved. Massless quanta experience zero proper time, so they don't experience intervals or distances. Massless quanta know nothing about our spacetime dimensions!
Anything that exists in the universe complies with these duality. Any phenomena or process we think that unfolds at the speed of light from our reference frame is, in fact, an instantaneous single event for the massless quanta or field disturbances involved.
So, in a literal way, speed of light is equivalent to instantaneity, because that is what you'll experience if you could travel at that speed. You'll feel leaving and arriving at the same time, no matter the distance travelled, or the time experienced by others.
The speed of light is not a speed, but a ratio. It dictates how a specific spacetime coordinate can connect to others. It is the rule for development of these instant connections. Massless carriers are like wormholes able to connect two different spacetime coordinates in no time (for themselves). There is no limit to how long or distant these instant connections may be, as long as they comply with the speed of light rule for development.
So the universe does not have to choose between time or timelessness. Every phenomena is both things at the same time: massless quanta experience a single "blink" of existence, yet they are the substrate that shapes the identity of every process, entity or property we can observe existing in nature.
You can read more about this here:
Hope you find it interesting.
