I agree with your points: though we didn't want to change the text on consequent loops (as the character only has a hint that it happens again) we've overlooked the experience of replaying a loop after loop for the player that wouldn't want to miss anything new. Definitely something to improve after the jam if we'll get to it.
In terms of "how long you're allowed to" - it's a bit differs from ending to ending. The one that, I think, you went for - indeed, required Loop 3(4?) to be able to pull it off, as it's not a conventional one, and the narrative was relying on it as well. While two other endings can be achieved on the first actual restart of the loop, as long as you know what to do - and that's some tricky nuance, haha.
But yup, that's something we just didn't have time to nail down, and where the player's feedback would be so crucial as well.
Thanks for playing and the good words!