POE I-94 with latest I-797 documentation

I have a couple of questions for an upcoming travel.
I am on H1B visa and my current visa is valid until Aug 20 2022. I have my h1b extension approved with start date:aug 21 2022 and end date: sep 2025 with same employer.

I am planning to travel to india and return USA 10 days before my current visa expires.Couldn’t secure a visa slot so far.
My questions:

  1. at PORT OF ENTRY on Aug 10 2022, does the CBP officer grant me I-94 until Aug 20 2022 or sep 2025?
  2. As my new approval notice starts in future(Aug 21 2022), can that be an issue to extend my I-94 as it didn’t officially start on Aug 10 2022.
  3. if I-94 is granted only till Aug 20 2022, how do I plan on extension or updating my I-94 after Aug 20 2022.
  4. or at the port of entry itself on Aug 10 2022, can CBP officer deny my entry and ask me to go home country and get stamped visa?

Appreciate your response.Thank you.