(speculating because I don't know the story in the comics): not interfering with Thanos is possibly compatible with whatever the sacred timeline is. That's the problem with time travel stories. They can bend back on themselves and in this one some entities can somehow stand outside of it in a way that lets them observe what's pre-determined to happen or within their desired parameters. So whatever happened to Thanos was forseeable and acceptably fits inside whatever their motivation is.
That's why loki is complete dogshit and almost feels like written by a kid that got no clue what he's doing.
Why would the avengers do anything ever? maybe u know the next threat to the earth is supposed to happen, so if me thor stops it, i will be janked like a ant of the street into a cub and judged + executed the next day because it was not supposed to do that, because it was probably supposed to happen. If not time keepers would probably send somebody to fix it.
And then what prevents another time keeper that sits above those time keepers to not interfear with loki trying to interfear with time. or correcting those time keepers?. And what about if we go another level up?
We know the time keepers are almighty powerful to the point anything in the series we saw are mere ants, because some random dude in a office just has 10 of those stones that basically are the mightiest items in the universe like its nothing.
Look thanos was a being that could exist, and he felt real because he also could be damaged and simple challenged. It gives it weight.
Loki series however honestly feels like complete dog shit from start to the end. It's almost watching a dbz episode, where freeze gains 10 ssj levels in 2 months of training. yet didn't bother to train when invading earth where the one guy that demolished him in seconds originated from. And he levels only to the point that he's on equal foot later in the series towards goku and not just spend another 1 month longer of training to absolute annihilate goku in seconds, yet loses again.
Zero thinking going on there.
But that's just the main story, the whole sets also made absolute no sense for multiple reasons, why even bother with paper lol, guess they needed something that looked interesting. Because it makes no sense at all. And the actors where dissapointing to say the least besides owen even loki itself wasn't much convincing.
Loki feels like a dumpster fire so far.