It can certainly be completed without spoilers, but it requires a bit of trial and error. I managed to ascend after 2-3 months of intense play...and a lot of dying. I think part of the joy of playing nethack is discovering how things work, so highly recommend not to read any spoilers. The best way to learn the mechanics is to install the game locally and play in explore mode. The game offers a lot of alternate ways to do stuff (because of conducts), but if you don't care about conducts characters tend to become a bit too powerful towards the end game. It's all a matter of surviving the early game, where you don't have resistances, skills etc. and where most people give up.
Playing without spoilers would be very challenging indeed. And you're right about the early game - there's a breakpoint where you've got enough food, hit points, AC, damage-dealing capability, and miscellaneous tricks (if you know how to use them) where the only think that's going to kill you is YASDing yourself. And then the game transforms into prepping (and prepping, and prepping some more) for the ascension run while staying alert enough that you don't YASD yourself because you forgot something or panicked. (You never have to panic in Nethack.)
