Blue is the Original Timeline
Yellow is the Revised Timeline
Red is the Deadpool 2 Timeline
The X-Men Timeline is a mess but I put it here as organized as possible. Dates might be off.
Tried to fill in the gap between Dark Phoenix and Logan as best as I could.
Got most Info from the X-Men Wiki https://xmenmovies.fandom.com/wiki/X-Men_Movies_Wiki
"There’s a theory in quantum physics that time is immutable. It’s like a river – you can throw a pebble in and create a ripple, but the current always corrects itself. No matter what you do the river just keeps flowing in the same direction."