Finished Season 3 before I left on vacation, since I just couldn't remember how everything ended. Mostly things were semi-reset
Now in Season 4, Homelander is feeling his age -- he's been collecting his white pubes in a jar, and he's been overhearing about all the digital effects needed to get rid of his skin folders. He's trying to invest in the future by setting up Ryan to be the future of America, while also inserting himself in Ryan's promotion to get more attention himself.
Season 4, Homelander's in a weird place because of this, and also because he has realized just killing everyone he doesn't like won't make his life any better and get him the validation he wants necessarily. He's also disgusted because everyone's scared of him and he can't get any straight answers from anyone -- no real advice, no real input, everyone just caters to whatever he asks. He proves this point by demanding that the Deep blow A-train in front of him, and Deep is really hesitant but goes to comply and everyone else is really uncomfortable too -- and so this is the opening to introduce Sister Sage.
Sister Sage is a supe whose power is being the smartest person on the planet. She's written and acted really well, in such a way that he wins Homelander's respect by telling him exactly what she thinks in a very blunt way but also in a way that doesn't lead to him killing her. She's the dissenting voice of reason he's been looking for, so much that she's invited to join the Seven. And so far, she's been proving herself to be smarter than everyone else in the room in carrying out an agenda to embody Homelander's vision of the future of the country and world. She's as bad as Stormfront in some ways, just without all the Nazi and fascist baggage.
But Homelander's worst enemy is himself. After Ryan sticks with him in Episode 1, some shit goes down in Episode 2 that leaves Ryan pretty distraught -- and Homelander manages to expose his own immature and dark soul to his son in a way that shakes Ryan to his core. All is not lost yet. By being himself, Homelander might yet turn Ryan back to the light.
I don't know if Firecracker gets on the Seven, as she seemingly fails her initiation -- but one cool thing is that she's played by the same actress who was so great as Emma in the early seasons of The Following.