I think Rammatra and Zenyatta's love towards each other are very mundane yet consuming. I'd say labelling it is too shallow, you can try to describe their relationship yet there is no words that can fully make one understand.
Zenyatta is the only one who Ramattra think understand him, and values him as Ramattra, not Ramattra the Ravenger or Null sector leader, just Ramattra, my brother.
Ramattra is the person who Zenyatta followed, despite being on separate paths and learning mondatta's teaching. He still have some of Ramattra's beliefs in him, I believe he still holds Ramattra in high regards.
The version of great love to each other exist, just in their memories when both are young and learning who they are after the war together. The question is as the world change, as they themselves change, do they still love each other in the wake of everything terrible that has happened?
Do they still love each other as they are no matter what has happened? Or are they merely trying to fit who they loved onto a stranger?
Does Zenyatta watch suffering families from null sectors invasion and wish he could hate Ramattra?
Does Ramattra wish he could feel anger at Zenyatta's inaction against the injustice omnics face?
They are like the sky and sea to me, two lonely blues forever separated by others or a thin invisible line both don't dare to cross.
I hope I describe what I think of them well enough