H1B Transfer to Employer B with approved PERM during 6th Year

[DMS2020]

Hi,
I'm currently working with Employer A as a Full time employee but he is not doing any Green Card and my Max out/I94 date will be May 20 2020. But I have an Employer B who started my GC process during last July, PERM applied on November 2019. Hoping to get my PERM on or before April 20 2020.

Scenario:

• PERM Approved on Apr 20
• Got a job between ~ Apr 25th and Apr 30

1) If My Employer B initiate transfer with approved PERM then what will be the expected decision/approval date from USCIS?
2) Will I get 1 year extension with approved PERM?
3) Will get approval only till May 2020 (max out)?
4) If transfer is not possible then i'm ready to go back to home country, what if - the COVID panic still exist and no flights after May 20? Can I still stay in USA without payroll, how long?

Please provide your valuable suggestions.
Thank you.