I really wasn't as confused by questions like "why didn't they go after steve, then?" as lots of people in this topic seem to be.
The TVA exists outside of time. They know what has happened and what is going to happen. They aren't surprised by Thanos, or the Avengers, or Steve Rodgers any more than you're surprised that when you open a door in your house your bathroom is on the other side.
They have the complete picture of the completely timeline. And in their complete picture, the avengers were supposed to do what they did. Loki was not supposed to do what he did. They aren't there to stop bad things like Thanos from happening. They are there to keep all events happening in the way they have foreseen. Things happening "correctly". So for anything they DIDNT correct, like Steve Rodgers, that obviously means that event wasn't a variant. That's it.
Now... are they being honest? Are they as infallible as they claim? Do they have a secret motivation for wanting to preserve a single timeline? Is all as it seems?
These are all questions the show may delve into. But the text of episode 1, as the TVA is presented to us now, is very clear cut in my opinion.
One scene that I don't think is getting much attention is the final one but before Variant Loki burns the Minutemen down. They report to what one quickly guesses is a time traveler setting themselves up for the future, and his immediate response is "eh, prune it before we have to write up paperwork."
The TVA is
bullshit. They're bureaucratic beyond absurdity and their standards are both super-strict and yet flexible enough to be arbitrary bordering on hypocritical - it honestly wouldn't even surprise me if Endgame Steve was "part of the plan"
somehow. And I'm pretty sure that bullshit is intentional, and not in a "roll with it so we don't have to explain it" kind of way. They are not a noble organization, and even if they aren't straight-up evil it's still unnerving seeing the TVA so above and beyond what the MCU has shown so far with seemingly no one else above them. Like, the entire Infinity Saga revolved around the awesome universal might of the Infinity Stones and yet the TVA offices pass them around like
cubicle swag, and one of them's got like 15 in his fucking desk.
Just jumping on it now, but I'm totally down with the theory that the TVA is going to end up severely weakened or even destroyed as a result of some amount of Loki burning-to-the-ground, which in turn opens up the MCU multiverse, something that What If, NWH, and MoM will all pick up on.