Well, as I promised - my little idea of ​​the Saburovs. I repeat, this is definitely not a canon or deep analysis, but rather... that version in the contest of which I like to think about them
To begin with, I really, Really like the bond between Alexander and Katerina

They trust each other and sincerely care. I definitely believe in their love, but... I see only friendly love. Not romantic. I understand that it wasn't planned this way, but I can't do anything with my perception
So for me, Katerina is a lesbian, and Alexander is gay

They were friends from early childhood, probably even the closest people to each other. Their marriage is a necessary measure in a homophobic world where they were born, raised and still live. Their already strong friendship was tightly sealed by a common secret, a common pain

And it seems to them that only they can understand each other. Over the years, they have become accustomed to the idea that the rest of the world will reject them. This is another reason why they cling to each other so much - because no one will help them except themselves

Decades of such a life do not pass in vain. I don't want to whitewash them, but Katerina broke down and became addicted to morphine including for this reason. Alexander is used to always suspecting the worst and protect Katerina, so he's so incredulous and sometimes aggressive

Similarly I imagine that Capella is a lesbian and Khan is gay. And the Saburovs are an example of who they will become in a couple of decades if they get married "because it is necessary." Closed, detached, completely unhappy

Of course, Katerina and Alexander support each other. Between them there is love, very strong, though not romantic. And if one of them mutually falls in love, the second won't feel loss, let alone jealousy. Only happiness that their friend finally finds true love

You already know that I ship Alexander with Victor. Katerina, it seems to me, would be a good couple for Lara. I really like that after so many years of loneliness and invisible isolation, the Saburovs can finally open up, be accepted and feel love. They deserve it.