As the question asks, I'm curious to know if just straight up doing the main storyline of the game will prevent me from playing quests from other NPCs or dungeons or whatnot. I should say right now that I have NOT finished the game even once at all and I've only reached the Greybeards.
So without any spoilers will there be quests from people I cannot activate because they either died, ran away, got killed or even dungeons that perhaps get closed off/become inaccessible, etc?
If there are then which ones are they? So that I can finish those first before losing the opportunity to do so. I don't actually have an interest in replaying this game anytime soon after I'm done with my first play-through which is why I want to experience as much of it as I can in the first run.
EDIT: So after reading the duplicate but not reading the spoilers on the linked duplicate, is it basically only once you've chosen a side on the war (i.e Imperials or Stormcloaks) that's the only "quest" that prevents the other side's quest from being accessible? So if I go with imperials i can't do stormcloak quests (obviously) but I presume that's the only case where such an example would occur? No other quest outright cancels out another line of quest?