Come back to US after 6 years with approved i140 or wait in US on H4?

Hi Anil, I am currently on H1B visa and my H1b max-out date is 20 Dec 2019 (6 years completed). Max-out date is calculated after considering the time out of US during H1b term.
My employer filed PERM in October 2019. My spouse is also working on H1b and currently in US. What are the option available to come back to US:

  1. Travel back to home country India on 20th Dec - Once PERM/I140 is approved and H1b extension is submitted and approved while I am in India, will I be able to travel back to US. Are their any rules/restrictions which stops me from traveling back?.

  2. Can i convert to H4 and stay in US until PERM/I140 & H1b is approved. Then switch it back to H1b?.

You can either convert to H4 and stay in US or come back on H1B after i140 and H1B extention approval.
Both options are fine.

Thanks for reply. Is it necessary to stay outside US for one year ?. I believe new H1B extension would be CAp exempt?. Is that right ?.

You will be cap exempt once i140 is approved.