So every rv character has a core trait, right? One that defines every action they take and that they generally are having to overcome in order to grow as people, e.g. Warren's tendency to run away from any possible problem/emotion ever.
I think something that will come up in s5 is Aubrey's trait: her refusal to let go of the past. There are many examples:
Her hatred towards Bryony is still as strong in 2064 as it was 44 years previous (even if she was in hypersleep for 20 years, that's still over 2 decades for her feelings to fade)
She's currently married to Hester (and they're adorable but that's besides the point), aka her ex from before 2020, meaning she still had feelings for her for potentially years after them breaking up
She fully admits that her mother's death is a major part of the reason why she's interested in cryonics
She still feels guilty about events that occurred 44 years ago despite a) them not being her fault and b) there being other, much easier targets to blame (aka Bryony)
And now, Warren and Gordon, the 2 people that she's tried the hardest to save, that she's sacrificed the security of her community for, want to leave and go into a dangerous world they know nothing about. And don't get me wrong, I understand why they do, Red Valley likely holds nothing but painful memories for either of them. But, to be honest, I'm unsure if she'll take it amazingly well in the beginning.