H1B transfer while H4EAD COS pending, valid I94

Hello - I read through the various threads but couldn’t find information related to my scenario hence this question.

Background :
I am an H1-B employee.

I was laid off on 7/14 (so the 60-day grace period is till 9/12).

Found another employer who will be applying for H1-B transfer but may not be able to do it before end of 60-day grace period i.e. 9/12.

Planning to apply for H4-EAD (based on spouse’s H1-B) before 9/12.
My I-94 (on the latest I-797A) expires in Jan 2021.

Question:
If new employer files for H1-B transfer before expiry of I-94, can I start work with them based on receipt of H1-B transfer papers?

If yes, is writing a letter of H4EAD withdrawal to the USCIS and certified mailing it to them a recommended approach to avoid further processing of H4EAD status?

If no, what do I have to do to start work with the new employer ASAP and discontinue by H4EAD application?

Thanks
A

Your H1B transfer should be approved to start working if you file the transfer after H1B 60 days grace is over.