H4 related question

I was on h1b visa and to leave my job in september and filed for h4 visa based on my spouse h1 which was valid till 06/30/2021.
i did not receive any response for h4 filed(COS) in us so once i left the country the h4 COS is no longer valid
I had to travel to india in January due to a medical emergecy for my mother(unfortunately she passed away)
My wife has applied for new H1 which is now approved from 07/01/2021 to 06/29/2024.

I am planning to apply for emergency h4 appointment (anywhere in india) and travel back in April.
If i use the current h1 petition(valid till 06/30/2021) will i be issued a visa only till 06/30/2021?
if i use the future date approved petition will i be eligible to travel only after 07/01/2021
Is there a way for me to get my h4 stamped till 06/29/2024 and still travel in april back to usa
what is the earliest date i need to take an appointment if i am using 07/01/2021 starting petition