Are you suggesting that things exists outside time? Because that has its own issues since existence is a time based concept. 'Outside time' isn't a concept, it's two words stuck together with no meaning.
Is existence dependent on time, or is it the other way round.
In other words is time just another emerged property?
If the universe has a starting point and evolved, when did time become a thing, in other words, when did it appear?
Does time pass when travelling at the speed of light? If not, according to your logic, how can it be said to even exist?
Existence due to time seems peculiarly physicalist and empirical to me.
The there are the linguistic consequences of what you are saying which is, the longer you exist, the more existent you are.
You never here that. Rather, You exist or you don't.
And finally there is the Religionethics effect where some atheists become, as part of a combined delusion, to think that they have settled the great philosophical questions whereas wider reading suggests that not to be the case.