H-4 to F-1 COS and H-4 extension

I am currently working for an employer on a H1-B status. My H-1B status was filed in Mar 2020 for extension and was approved with a validity until April 2023. I have the approved i797 form also. But, during my extension filing last year, my employer did not file H-4 extension for my wife who is on a H-4 Visa which is going to expire in July 2021. So technically she can go out of status after Jul 2021 if nothing is done. However, in Aug 2020 my wife joined school for MS and applied for H-4 to F-1 Change of Status(COS) in Oct 2020 which is still pending with USCIS. She got her biometrics in Apr 2021.

Since there are only two months left for her H-4 to expire and considering the slow process of COS, I want to know-

  1. Should I apply for H-4 extension and when and how.
  2. Will the H-4 extension application void the current H-4 to F-1 COS application.
  3. And if F1 is approved first and H-4 extension is approved later, then is there a risk of going back to
    H-4 again. How can this be solved?

You can file H4 extension but then which application gets approved last will define the status.