I agree with the premise, but when it comes to the HM and EM primals or Ultima Weapon redux, you might as well just look up some pointers. You're not going to spoil yourself anything that way, story-wise, they're still pretty tricky even if you have a general idea of what's going to happen. Which is only a beefed up version of the easier versions you've done. You will still need to build some routine and practice, and have a good group you can rely on.
In terms of the story and all the pre-endgame content, I think it's ridiculous how people expect newbies to look everything up. For one, they're not that hard, for another, it'll only spoil bits of the story and the learning experiences that are involved in figuring them out.
My final point is that just knowing the fight is nothing after a certain point. Titan HM is a good example of practice making perfect. Just knowing the general order of phases and events in it will not help you win it easily unless you're being carried.