1 month until the exam - tips for quant

Hello,

I scheduled my exam for the 24th of October and my goal is to score 700+. I am currently doing the e-gmat course for SC, since I've figured out that this is my weak are in Verbal. I am quite confident with CR and for the RC part I figured out that it works best for me to carefully read the entire passage first and take notes. That's why I'll try to save some time in the SC and CR questions to use the spare time for RC.

Quant: my biggest issue
I can easily solve all/most of the sub 600 and 600-700 questions, but I am still struggeling with the ones at the end of OG quant review (after number 110). I also solved some questions of the free gmat club test (quant part) and found the majority of them quite hard.
What are the best resources for practicing hard questions? should I only focus on the OG questions?
I attended an e-gmat webinar on number properties the other day, where they solved 720+ DS questions, but I am not sure if this makes a lot of sense since I think I should get 100% confident with 600-700/700 questions first.

What about MGMAT CAT tests? I've read that the quant part is harder than the actual exam? Would it make sense to start solving those questions or should I first focus on easier ones?
Any insides on this?

Thank you!

edit: Is there a resource where OFFICIAL questions are split into difficulty level & topic?