H1B Approved filling DS 160 and interview slot booking

I got an approval for 2021 h1b cap now i am planning to fill the ds-160 and book the slot in this month for interview.
my passport will expires in 2021 November and i got confirmation from passport customer care(india) that i can’t apply for renewal if the passport validity is having more than a year and Planning to apply for renewal in November 2020.

1).if I attend interview with old passport Will it be effect on visa stamping duration?
2).can i carry two passport for interview if i get renewal passport before the interview?

please suggest me the best way.