EB2 to EB3 from old employer pros and cons

Background information-
Old Employer filed for PERM in EB2 category.
My priority date: April 2014,
I-140 approval date: Feb 2016,
First 3 year extension based on i140 expired in May 2019,
Second 3 year extension based on i140 to expire in May 2022,

Joined new employer in February 2020,
New employer got H1B extension till February 2023 based on my old i140 from previous employer.
New employer has not started GC process yet.

Questions-
With all above background information what should I do?

  1. Should I contact previous employer to check if they can retrograde from EB2 to EB3? Can they do it? If yes, what’s the cost towards that?

  2. I am not sure if previous employer has revoked i140. How can I check that? I don’t want my request to employer make them think otherwise and revoke i140. I am in extremely good terms with my previous employer but just want to make sure.

  3. If previous employer changes from EB2 to EB3 then can I file for 485 on my own? Or it needs to be done by same old employer?

  4. If previous employer changes from EB2 to EB3 then can I ask my current employer to just file for 485?

  5. Should I ask my new employer to start GC in EB3 ?

I read thru that forum and it doesn’t answer all questions.