But here is the dirty secret nobody tells you on test day: You don't have to finish UWorld to pass. You just have to learn from it correctly.
Why? Because Step 1 is a thinking exam, not a memorization exam. If you get a question wrong in Timed mode, you panic, look at the answer, say "Oh, duh," and move on. You learn nothing.
If you are studying for Step 1, you have heard the gospel: UWorld is the gold standard.