Timelines? *potential spoliers*

Happy (possibly belated) new years everybody! I’ve just seen Mufasa for the first time yesterday, and i have some.. questions?

I’ve read some of you speaking about potential different canon timelines. How TLG is different timeline than 1, 2 and 1/2, and the possibility of “Kopa” at the end of 1 (and some books apparently as well?)

Now what I’m confused about is, if TLG and the other three are different timelines, then is Mufasa its own as well? In the beginning of the movie, Nala is giving birth to Kion, and according to TLG, Taka got the scar from the snake and struggling to maintain the combo of the intensity of the roar and the poison. However in Mufasa, obviously the story is told completely different. What’s canon and what isn’t? I’ve seen so many mixed opinions on what is and isn’t BELIEVED to be canon. What is, factually, canon?

One theory i’ve seen is when Kion took the trip to the tree of life to get the poison cured that the entirety of TLK2 took place, hence why Kion never “existed” in the movie. However, the timeline seems so short when you combine TLG and TLK2. That seems somewhat believable. But then the whole backstory of the guard and Taka and the snake and Askari and all that is obviously WAY different than how Mufasa is told. So one voids the other out almost entirely, unless they are in different timelines.