It will focuse on young furiosa. I hope they make the sequel first, but I'm excited about anything that happens in the Mad Max world. Hell I'd really like if they would make a sequel to the video game too.
https://fullcirclecinema.com/2020/03/07/mad-max-prequel-furiosa/
They should make a TV show about Max traveling around in the wastes just trying to survive and getting sucked in time and again to help people who are less fortunate than even he - the wasteland nomad.
If they were going to do anything with Furiosa, I'd rather it was a sequel with her trying to turn Immortan Joe's cult-gang around into a haven/utopia/oasis. And, of course, defend it from raiders with lots of boom-boom sticks. A prequel isn't that interesting to me; I got her backstory in Fury Road. What happens next is intriguing, not so much what came before.