I just finished this season. I almost didn't watch because I wasn't a huge fan of Season 2. However, I'm glad I did watch. It was a good season with an ending that was very realistic. Despite the gang having been friends for a long time, those high school friendships don't always last forever. People do grow apart and move on. And considering the devastating experiences the friends had together and that they all lost themselves in the Rollerworld case, to the point of actually plotting a murder, I can see how that would cause an estrangement amongst them. They don't hate each other, but because of what they almost did, they made the decision to move on from each other.
I was surprised to see Jamal playing football too. But again, when thinking about what he (and his friends) had been through over the past couple of years, it made sense that he would seek out some sense of normalcy.
Jasmine finally got Rudy, which means he doesn't have to masturbate anymore, or perhaps not as much. LOL. Spooky likely used the Rollerworld money to exchange his gang life for a normal life. And Cesar, who was always teetering on the edge of criminality, finally went dark side, when Monse found a new life, new friends etc., at the boarding school and likely broke up with him; his friendship with Jamal and Ruby never recovered and his father likely never returning to the neighborhood. Ironically, he now has the rage that was driving Spooky all those years. I think he always had it but that his friendships with Monse, Ruby and Jamal saved him. When they disappeared from his life, he embraced the rage and subsequently the gang life.
I was satisfied with this ending and don't need another season. Like others, I think it is a good series finale.