I don't think that Serena will ever help June.
They hate each other, and Serena has two reasons to fuel that hate.
June can have a baby, but worse, June is having Serena's baby.
Serena would be jealous of anyone able to get pregnant, but it's killing her now that she has to rely on June to have 'her' baby.
I don't want to call Serena strong because ultimately I believe that the people who created Gilead are selfish, weak, spoilt bullies, basically they are pampered children who want their own way and somehow they've managed to get it using terrorist tactics and religious doctrines.
Look at the Commanders having their clay pigeon shoot, they were like bickering children. And the wives at the baby shower, running around with a little push along toy and laughing and clapping. They were like children themselves.
So Serena in one way can do all of this, she can plot and plan to destroy a powerful country and put her husband into a position of power (hopefully more precarious than they know), and she can accept the idea of raping women on a monthly basis to get the baby she wants, she's selfish and crazy enough to believe that having power makes that baby hers and not June's, but she can't deal with the reality of having that woman in her home and she doesn't have the power to get her out. Fred basically refused to send June away when Serena asked.
So she's poisoned by the thought that even though she's getting the baby she's always wanted, she needs June and she resents that and hates it and hates June.
Some people just do hate the person who is giving them what they want. Serena has form for that, she wanted Gilead but now she's powerless when she's used to being powerful. So she has to take power where she can find it, in violence to women trapped in her home and her fucked up Utopia that's taken everything from her. Even Fred, because I think before Gilead, when it was still being planned, Fred loved her and was faithful to her, and they were equal. Now she's below him in status, he's got a 'god-given right' to be unfaithful and to rape a women in front of her every month, and I don't think he loves her any more.
She has everything she ever wanted right now and she's hating it. That hate needs a focus and that focus is June.
I worry about that baby as well. Especially if it's a girl. Sooner or later if Serena and the Commander get to raise the baby, she will see June in it somewhere as it grows up and that will anger her.
She's an angry, violent women and she won't want a single reminder of June in that baby. If it grows up to look or act like June Serena won't be able to stand it.