The concept of time is complex and can be understood and experienced in different ways. While it is true that after death, there is no consciousness or subjective experience, making it difficult to measure the passing of time, it is not accurate to say that "time doesn't exist" after we die.
When we refer to the experience of time, it is typically tied to our conscious awareness and perception. In that sense, without consciousness, there is no subjective experience of time. From the perspective of a deceased individual, there is no perception of the passing of time, and therefore, it would not feel like a trillion years or any duration at all.
However, it's important to note that the concept of time as we understand it is a human construct used to measure and organize events and changes in the universe. Time exists as a fundamental aspect of the physical universe, and it continues to pass even if we are not conscious of it.
Therefore, it is not accurate to say that a trillion years would feel like a second after death because there would be no experience or perception of time at all.