Well, I'm not sure whether my experience will be useful or not, since it was a long-term strategy and you don't have that much time left if you're going to apply soon.
I took an official test about 1 year before applications, with little preparation. I didn't expect a good score, but at least I'd know how far I was from my goal. I had taken a couple of mock tests before that, I guess, and the results looked weird to me.
Instead of focusing on the score I was getting from mock tests that seemed unreliable, I focused on how much I was improving. I had a spreadsheet showing the percentage of questions that I was getting right, for each category (easy, medium, hard). So, I was able to track my improvement in each category over time.
After about 8 months, it was clear to me that I was getting a much higher percentage of questions right. I also knew my strengths and weaknesses. And I had a much better strategy for the exam, something that I didn't have before.
So, I didn't know what score to expect, but at least I knew it should be much better than my previous official score. I saw that I wasn't making dumb mistakes with easy questions, and that I had a pretty good performance with medium questions. For the hard questions, I knew the types of questions that required a long time for me to solve, that I should be very careful about, that I should just skip because I usually spent too much time on them and still got the wrong answer, or that I had a good chance of getting right.
If you kept track of your performance over time like me, you can use that to see when you achieve much better results and feel when you are ready for another attempt. You should also be able to focus on what needs to be improved, and not waste time with things in which you are already good enough. What topics, what levels of difficulty you should pay more attention to. But if you didn't keep any records like that, then maybe it is too late to start now.