What If I Don't Want What's at the Top of the Ladder?
Because the ladder answers a different question than the one you're actually asking. The ladder tells you what's next. It has never once told you whether the destination is yours.
The ladder is inherited, not chosen
Most people don't choose the ladder after examining it — they inherit it, because it offers something purpose doesn't: a visible sequence, external validation at every rung, and proof of progress you can point to. None of that requires you to have first decided the top is somewhere you want to be.
Unease is information
The unease isn't a signal that you've failed. It's information. It means the climbing has been running on autopilot longer than the direction has been examined — and autopilot doesn't check in with you until you're already several rungs past the point where checking would have been useful.
You don't have to get off the ladder to answer this. You have to ask, honestly, whether the specific direction you're climbing in was ever actually chosen — or just the first one that offered a way to keep moving.