I used Virtual Aviation for sim prep for my RYR assessment day. It was an expensive gamble. I felt comfortable, well-prepared and confident during my subsequent sim assessment. I passed the assessment and have been flying for RYR for 18 months.
But the guy with whom I did the sim prep was also paired with me during the RYR assessment. Sadly he failed the assessment. He had been fine in the sim prep but had a bad day with RYR. So, please note that paying for sim prep is no guarantee that you will pass.
My best advice is to prepare very carefully using the information from the Briefing Pack. If you prepare well, you're more likely to be relaxed and perform to your potential. The assessors are not looking for perfection. They want to see potential to pass a Boeing 737-800 type rating.
Good luck, but before you apply, do read the threads on Terms and Conditions about life in RYR at the moment. It's not good news.