As soon as he did something that would have interfered with the timeline the TVA took him.But he peaced out the timeline in 2012 right? He can always come back and avoid being Thanos neck-snapped for real without fucking up that one timeline (Dr Strange intensifies).
As for the main Loki of this show he doesn't need to do that, his timeline is gone and the TVA is probably not gonna be around after this, or at least not with the same role, so if our new Loki survives this show he can just go off wherever he wants.