Scrum Open vs. PSM I assessment

I tried to do the PSM I assessment today after studying 4 guides, reading the Agile Project Management WIth Scrum, attending a course, finishing the Scum Open a few times with 100%, doing some research and with some years of experience working on Dev Teams and with Scrum.

Unfortunately I failed to pass with a 82% final score.

I first realized that I could almost automatically reply questions that were similar on the Scrum Open, but I was surprised that if the Scrum Open difficulty is 2, then the exam has difficulty 5. It has nothing to do with it. While on the Scrum Open you have direct questions about selecting 2 possible answers, here you have a few questions asking to select whatever response you think it could be true.

Also that if you take longer in some response, you won't have any time to come back to review your doubts at the end (only 45 seconds / question).

What most concerns me, and I am wondering if I will repeat the exam, it's because I have to pay the tax again for this 3% without any discount :(

I believe the exam with the multiple choices and random questions is just a question of luck.

Do you think I should repeat it? How can I study harder? My time is getting limited and I don't think repeating the Scrum Open is a good thing, as the questions I get are always the same, only in diffrent random positions.

Thanks