How did Deadpool know about Logan?

I’ve been thinking of the timeline after reading an article from itechpost that also matches with the data on

It states the order of how Deadpool 2 and Logan plays out together in chronological order. This said, it’s been quite a mission to complete the “occuring movie years” for the X-men Legacy since Fox practically destroyed the timelines with reboots and such – and I’m much aware of the fact that Deadpool 2 occurs long before Logan.

I’m of course also aware of the default 4th walling here and that Deadpool might know about those events due to this. And I guess that there has been quite a time traveling, according to the post credit scenes since then. But shouldn’t this occur in some kind of reverse order? If Deadpool 2 begins with a “Death of Logan” reference, and ends with Deadpool time traveling – how could he possibly know?